ON PERSONNEL AND EQUIPMENT
This chapter describes the desert environment
and how it affects personnel and equipment.
Successful desert operations require adaptation
to the environment and to the limitations its terrain and climate
impose. Equipment and tactics must be modified and adapted to
a dusty and rugged landscape where temperatures vary from extreme
highs down to freezing and where visibility may change from 30
miles to 30 feet in a matter of minutes. Deserts are arid, barren
regions of the earth incapable of supporting normal life due to
lack of water. See Figure 1-1 for arid regions of the world. Temperatures
vary according to latitude and season, from over 136 degrees Fahrenheit
in the deserts of Mexico and Libya to the bitter cold of winter
in the Gobi (East Asia). In some deserts, day-to-night temperature
fluctuation exceeds 70 degrees Fahrenheit. Some species of animal
and plant life have adapted successfully to desert conditions
where annual rainfall may vary from 0 to 10 inches.
Desert terrain also varies considerably from
place to place, the sole common denominator being lack of water
with its consequent environmental effects, such as sparse, if
any, vegetation. The basic land forms are similar to those in
other parts of the world, but the topsoil has been eroded due
to a combination of lack of water, heat, and wind to give deserts
their characteristic barren appearance. The bedrock may be covered
by a flat layer of sand, or gravel, or may have been exposed by
erosion. Other common features are sand dunes, escarpments, wadis,
and depressions. This environment can profoundly affect military
operations. See Figure 1-2 for locations of major deserts of the
world, and Appendix A for additional information on desert countries
of the world.
It is important to realize that deserts are affected
by seasons. Those in the Southern Hemisphere have summer between
21 December and 21 March. This 6-month difference from the United
States is important when considering equipping and training nonacclimatized
soldiers/marines for desert operations south of the equator.
Key terrain in the desert is largely dependent
on the restrictions to movement that are present. If the desert
floor will not support wheeled vehicle traffic, the few roads
and desert tracks become key terrain. Crossroads are vital as
they control military operations in a large area. Desert warfare
is often a battle for control of the lines of communication (LOC).
The side that can protect its own LOC while interdicting those
of the enemy will prevail. Water sources are vital, especially
if a force is incapable of long distance resupply of its water
requirements. Defiles play an important role, where they exist.
In the Western Desert of Libya, an escarpment that paralleled
the coast was a barrier to movement except through a few passes.
Control of these passes was vital. Similar escarpments are found
in Saudi Arabia and Kuwait.
Types of Desert Terrain
There are three types of desert terrain: mountain,
rocky plateau, and sandy or dune terrain. The following paragraphs
discuss these types of terrain.
Mountain deserts are characterized by scattered
ranges or areas of barren hills or mountains, separated by dry,
flat basins. See Figure 1-3 for an example of mountain desert
terrain. High ground may rise gradually or abruptly from flat
areas, to a height of several thousand feet above sea level. Most
of the infrequent rainfall occurs on high ground and runs off
in the form of flash floods, eroding deep gullies and ravines
and depositing sand and gravel around the edges of the basins.
Water evaporates rapidly, leaving the land as barren as before,
although there may be short-lived vegetation. If sufficient water
enters the basin to compensate for the rate of evaporation, shallow
lakes may develop, such as the Great Salt Lake in Utah or the
Dead Sea; most of these have a high salt content.
Rocky Plateau Deserts
Rocky plateau deserts are extensive flat areas
with quantities of solid or broken rock at or near the surface.
See Figure 1-4 for an example of a rocky plateau desert. They
may be wet or dry, steep-walled eroded valleys, known as wadis,
gulches, or canyons. Narrow valleys can be extremely dangerous
to men and materiel due to flash flooding after rains; although
their flat bottoms may be superficially attractive as assembly
areas. The National Training Center and the Golan Heights are
examples of rocky plateau deserts.
Sandy or Dune Deserts
Sandy or dune deserts are extensive flat areas
covered with sand or gravel, the product of ancient deposits or
modern wind erosion. "Flat" is relative in this case,
as some areas may contain sand dunes that are over 1,000 feet
high and 10-15 miles long; trafficability on this type of terrain
will depend on windward/leeward gradients of the dunes and the
texture of the sand. See Figure 1-5 for an example of a sandy
desert. Other areas, however, may be totally flat for distances
of 3,000 meters and beyond. Plant life may vary from none to scrub,
reaching over 6 feet high. Examples of this type of desert include
the ergs of the Sahara, the Empty Quarter of the Arabian desert,
areas of California and New Mexico, and the Kalahari in South
Africa. See Figure 1-6 for an example of a dune desert.
Roads and trails are rare in the open desert.
Complex road systems beyond simple commercial links are not needed.
Road systems have been used for centuries to connect centers of
commerce, or important religious shrines such as Mecca and Medina
in Saudi Arabia. These road systems are supplemented by routes
joining oil or other mineral deposits to collection outlet points.
Some surfaces, such as lava beds or salt marshes, preclude any
form of routine vehicular movement, but generally ground movement
is possible in all directions. Speed of movement varies depending
on surface texture. Rudimentary trails are used by minor caravans
and nomadic tribesmen, with wells or oases approximately every
20 to 40 miles; although there are some waterless stretches which
extend over 100 miles. Trails vary in width from a few meters
to over 800 meters.
Vehicle travel in mountainous desert country
may be severely restricted. Available mutes can be easily blinked
by the enemy or by climatic conditions. Hairpin turns are common
on the edges of precipitous mountain gorges, and the higher passes
may be blocked by snow in the winter.
The following terrain features require special
considerations regarding trafficability.
Wadis or dried water courses, vary from wide,
but barely perceptible depressions of soft sand, dotted with bushes,
to deep, steep-sided ravines. There frequently is a passable route
through the bottom of a dried wadi. Wadis can provide cover from
ground observation and camouflage from visual air reconnaissance.
The threat of flash floods after heavy rains poses a significant
danger to troops and equipment downstream. Flooding may occur
in these areas even if it is not raining in the immediate area.
See Figure 1-7 for an example of a wadi.
Salt marsh (sebkha) terrain is impassable to
tracks and wheels when wet. When dry it has a brittle, crusty
surface, negotiable by light wheel vehicles only. Salt marshes
develop at points where the water in the subsoil of the desert
rose to the surface. Because of the constant evaporation in the
desert, the salts carried by the water are deposited, and results
in a hard, brittle crust.
Salt marshes are normally impassable, the worst
type being those with a dry crust of silt on top. Marsh mud used
on desert sand will, however, produce an excellent temporary road.
Many desert areas have salt marshes either in the center of a
drainage basin or near the sea coast. Old trails or paths may
cross the marsh, which are visible during the dry season but not
in the wet season. In the wet season trails are indicated by standing
water due to the crust being too hard or too thick for it to penetrate.
However, such routes should not be tried by load-carrying vehicles
without prior reconnaissance and marking. Vehicles may become
mired so severely as to render equipment and units combat ineffective.
Heavier track-laying vehicles, like tanks, are especially susceptible
to these areas, therefore reconnaissance is critical.
The ruins of earlier civilizations, scattered
across the deserts of the world, often are sited along important
avenues of approach and frequently dominate the only available
passes in difficult terrain. Control of these positions maybe
imperative for any force intending to dominate the immediate area.
Currently occupied dwellings have little impact on trafficability
except that they are normally located near roads and trails. Apart
from nomadic tribesmen who live in tents (see Figure 1-8 for an
example of desert nomads), the population lives in thick-walled
structures with small windows, usually built of masonry or a mud
and straw (adobe) mixture. Figure 1-9 shows common man-made desert
Because of exploration for and production of
oil and other resources, wells, pipelines, refineries, quarries,
and crushing plants may be of strategic importance in the desert.
Pipelines are often raised 1 meter off the ground-where this is
the case, pipelines will inhibit movement. Subsurface pipelines
can also be an obstacle. In Southwest Asia, the subsurface pipelines
were indicated on maps. Often they were buried at such a shallow
depth that they could be damaged by heavy vehicles traversing
them. Furthermore, if a pipeline is ruptured, not only is the
spill of oil a consideration, but the fumes maybe hazardous as
Agriculture in desert areas has little effect
on trafficability except that canals limit surface mobility. Destruction
of an irrigation system, which may be a result of military operations,
could have a devastating effect on the local population and should
be an important consideration in operational estimates. Figure 1-10 shows an irrigation ditch.
The highest known ambient temperature recorded
in a desert was 136 degrees Fahrenheit (58 degrees Celsius). Lower
temperatures than this produced internal tank temperatures approaching
160 degrees Fahrenheit (71 degrees Celsius) in the Sahara Desert
during the Second World War. Winter temperatures in Siberian deserts
and in the Gobi reach minus 50 degrees Fahrenheit (minus 45 degrees
Celsius). Low temperatures are aggravated by very strong winds
producing high windchill factors. The cloudless sky of the desert
permits the earth to heat during sunlit hours, yet cool to near
freezing at night. In the inland Sinai, for example, day-to-night
temperature fluctuations are as much as 72 degrees Fahrenheit.
Desert winds can achieve velocities of near hurricane
force; dust and sand suspended within them make life intolerable,
maintenance very difficult, and restrict visibility to a few meters.
The Sahara "Khamseen", for example, lasts for days at
a time; although it normally only occurs in the spring and summer.
The deserts of Iran are equally well known for the "wind
of 120 days," with sand blowing almost constantly from the
north at wind velocities of up to 75 miles per hour.
Although there is no danger of a man being buried
alive by a sandstorm, individuals can become separated from their
units. In all deserts, rapid temperature changes invariably follow
strong winds. Even without wind, the telltale clouds raised by
wheels, tracks, and marching troops give away movement. Wind aggravates
the problem. As the day gets warmer the wind increases and the
dust signatures of vehicles may drift downwind for several hundred
In the evening the wind normally settles down.
In many deserts a prevailing wind blows steadily from one cardinal
direction for most of the year, and eventually switches to another
direction for the remaining months. The equinoctial gales raise
huge sandstorms that rise to several thousand feet and may last
for several days. Gales and sandstorms in the winter months can
be bitterly cold. See Figure 1-11 for an example of wind erosion.
Sandstorms are likely to form suddenly and stop
just as suddenly. In a severe sandstorm, sand permeates everything
making movement nearly impossible, not only because of limited
visibility, but also because blowing sand damages moving parts
The lack of water is the most important single
characteristic of the desert. The population, if any, varies directly
with local water supply. A Sahara oasis may, for its size, be
one of the most densely occupied places on earth (see Figure 1-12
for a typical oasis).
Desert rainfall varies from one day in the year
to intermittent showers throughout the winter. Severe thunderstorms
bring heavy rain, and usually far too much rain falls far too
quickly to organize collection on a systematic basis. The water
soon soaks into the ground and may result in flash floods. In
some cases the rain binds the sand much like a beach after the
tide ebbs allowing easy maneuver however, it also turns loam into
an impassable quagmire obstacle. Rainstorms tend to be localized,
affecting only a few square kilometers at a time. Whenever possible,
as storms approach, vehicles should move to rocky areas or high
ground to avoid flash floods and becoming mired.
Permanent rivers such as the Nile, the Colorado,
or the Kuiseb in the Namib Desert of Southwest Africa are fed
by heavy precipitation outside the desert so the river survives
despite a high evaporation rate.
Subsurface water may be so far below the surface,
or so limited, that wells are normally inadequate to support any
great number of people. Because potable water is absolutely vital,
a large natural supply may be both tactically and strategically
important. Destruction of a water supply system may become a political
rather than military decision, because of its lasting effects
on the resident civilian population.
When there is no surface water, tap into the
earth's water table for ground water. Access to this table and
its supply of generally pure water depends on the contour of the
land and the type of soil. See Figure 1-13 for water tables.
From Rocky Soil
Look for springs and seepages. Limestone has
more and larger springs than any other type rock. Because limestone
is easily dissolved, caverns are readily etched in it by ground
water. Look in these caverns for springs. Lava rock is a good
source of seeping ground water because it is porous. Look for
springs along the walls of valleys that cross the lava flow. Look
for seepage where a dry canyon cuts through a layer of porous
Watch for water indicators in desert environments.
Some signs to look for are the direction in which certain birds
fly, the location of plants, and the convergence of game trails.
Asian sand grouse, crested larks, and zebra birds visit water
holes at least once a day. Parrots and pigeons must live within
reach of water. Cattails, greasewoods, willows, elderberry, rushes,
and salt grass grow only where ground water is near the surface.
Look for these signs and dig. If you do not have a bayonet or
entrenching tool, dig with a flat rock or sharp stick.
Desert natives often know of lingering surface
pools in low places. They cover their surface pools, so look under
brush heaps or in sheltered nooks, especially in semiarid and
Places that are visibly damp, where animals have
scratched, or where flies hover, indicate recent surface water.
Dig in such places for water. Collect dew on clear nights by sponging
it up with a handkerchief. During a heavy dew you should be able
to collect about a pint an hour.
Dig in dry stream beds because water may be found
under the gravel. When in snow fields, put in a water container
and place it in the sun out of the wind.
If unsuccessful in your search for ground or
runoff water, or if you do not have time to purify the questionable
water, a water-yielding plant may be the best source. Clear sap
from many plants is easily obtained. This sap is pure and is mostly
Plant tissues. Many
plants with fleshy leaves or stems store drinkable water. Try
them wherever you find them. The barrel cactus of the southwestern
United States is a possible source of water (see Figure 1-14).
Use it only as a last resort and only if you have the energy to
cut through the tough, spine-studded outer rind. Cut off the top
of the cactus and smash the pulp within the plant. Catch the liquid
in a container. Chunks may be carried as an emergency water source.
A barrel cactus 3-1/2 feet high will yield about a quart of milky
juice and is an exception to the rule that milky or colored sap-bearing
plants should not be eaten.
Roots of desert plants.
Desert plants often have their roots near
the surface. The Australian water tree, desert oak, and bloodwood
are some examples. Pry these roots out of the ground, cut them
into 24-36 inch lengths, remove the bark, and suck the water.
all vines yield palatable water, but try any vine found. Use the
following method for tapping a vine--it will work on any species:
Step 1. Cut a deep notch in the vine as high
up as you can reach.
Step 2. Cut the vine off close to the ground
and let the water drip into your mouth or into a container.
Step 3. When the water ceases to drip, cut another
section off the top. Repeat this until the supply of fluid is
coconut, sugar and nipa palms contain a drinkable sugary fluid.
To start the flow in coconut palm, bend the flower stalk downward
and cut off the top. If a thin slice is cut off the stalk every
12 hours, you can renew the flow and collect up to a quart a day.
green coconuts. They can be opened easily with a knife and they
have more milk than ripe coconuts. The juice of a ripe coconut
is extremely laxative; therefore, do not drink more than three
or four cups a day.
The milk of a coconut can be obtained by piercing
two eyes of the coconut with a sharp object such as a stick or
a nail. To break off the outer fibrous covering of the coconut
without a knife, slam the coconut forcefully on the point of a
rock or protruding stump.
Survival Water Still
build a cheap and simple survival still that will produce drinking
water in a dry desert. Basic materials for setting up this still
- 6-foot square sheet of clean plastic.
- A 2- to 4-quart capacity container.
- A 5-foot piece of flexible plastic tubing.
Pick an unshaded spot for the still, and dig
a hole. If no shovel is available, use a stick or even your hands.
The hole should be about 3 feet across for a few inches down,
then slope the hole toward the bottom as shown in Figure 1-15
which depicts a cross section of a survival still. The hole should
be deep enough so the point of the plastic cone will be about
18 inches below ground and will still clear the top of the container.
Once the hole is properly dug, tape one end of the plastic drinking
tube inside the container and center the container in the bottom
of the hole. Leave the top end of the drinking tube free, lay
the plastic sheet over the hole, and pile enough dirt around the
edge of the plastic to hold it securely. Use a fist-size rock
to weight down the center of the plastic; adjust the plastic as
necessary to bring it within a couple of inches of the top of
the container. Heat from the sun vaporizes the ground water. This
vapor condenses under the plastic, trickles down, and drops into
The indigenous vegetation and wildlife of a desert
have physiologically adapted to the conditions of the desert environment.
For example, the cacti of the American desert store moisture in
enlarged stems. Some plants have drought-resistant seeds that
may lie dormant for years, followed by a brief, but colorful display
of growth after a rainstorm. The available vegetation is usually
inadequate to provide much shade, shelter, or concealment, especially
from the air. Some plants, like the desert gourd, have vines which
grow to 4.5 meters (15 feet). Others have wide lateral roots just
below the surface to take advantage of rain and dew, while still
others grow deep roots to tap subsurface water. Presence of palm
trees usually indicates water within a meter of the surface, salt
grass within 2 meters, cottonwood and willows up to 4 meters.
In addition to indicating the presence of water, some plants are
Invertebrates such as ground-dwelling spiders,
scorpions, and centipedes, together with insects of almost every
type, are in the desert. Drawn to man as a source of moisture
or food, lice, mites, and flies can be extremely unpleasant and
carry diseases such as scrub typhus and dysentery. The stings
of scorpions and the bites of centipedes and spiders are extremely
painful, though seldom fatal. Some species of scorpion, as well
as black widow and recluse spiders, can cause death. The following
paragraphs describe some of the wildlife that are encountered
in desert areas and the hazards they may pose to man.
Scorpions are prevalent in desert regions. particularly
active at night. Scorpions are They prefer damp locations and
are easily recognizable by their crab-like appearance, and by
their long tail which ends in a sharp stinger. Adult scorpions
vary from less than an inch to almost 8 inches in length. Colors
range from nearly black to straw to striped. Scorpions hide in
clothing, boots, or bedding, so troops should routinely shake
these items before using. Although scorpion stings are rarely
fatal, they can be painful.
Flies are abundant throughout desert environments.
Filth-borne disease is a major health problem posed by flies.
Dirt or insects in the desert can cause infection in minor cuts
Avoid all dogs and rats which are the major carriers
of fleas. Fleas are the primary carriers of plague and murine
Reptiles are perhaps the most characteristic
group of desert animals. Lizards and snakes occur in quantity,
and crocodiles are common in some desert rivers. Lizards are normally
harmless and can be ignored; although exceptions occur in North
America and Saudi Arabia.
Snakes, ranging from the totally harmless to
the lethal, abound in the desert. A bite from a poisonous snake
under two feet long can easily become infected. Snakes seek shade
(cool areas) under bushes, rocks, trees, and shrubs. These areas
should be checked before sitting or resting. Troops should always
check clothing and boots before putting them on. Vehicle operators
should look for snakes when initially conducting before-operations
maintenance. Look for snakes in and around suspension components
and engine compartments as snakes may seek the warm areas on recently
parked vehicles to avoid the cool night temperatures.
Sand vipers have two long and distinctive fangs
that may be covered with a curtain of flesh or folded back into
the mouth. Sand vipers usually are aggressive and dangerous in
spite of their size. A sand viper usually buries itself in the
sand and may strike at a passing man; its presence is alerted
by a characteristic coiling pattern left on the sand.
The Egyptian cobra can be identified by its characteristic
cobra combative posture. In this posture, the upper portion of
the body is raised vertically and the head tilted sharply forward.
The neck is usually flattened to form a hood. The Egyptian cobra
is often found around rocky places and ruins and is fairly common.
The distance the cobra can strike in a forward direction is equal
to the distance the head is raised above the ground. Poking around
in holes and rock piles is particularly dangerous because of the
likelihood of encountering a cobra. See Figure 1-16 for an example
of a viper and cobra.
The camel is the best known desert mammal. The
urine of the camel is very concentrated to reduce water loss,
allowing it to lose 30 percent of its body weight without undue
distress. A proportionate loss would be fatal to man. The camel
regains this weight by drinking up to 27 gallons (120 liters)
of water at a time. It cannot, however, live indefinitely without
water and will die of dehydration as readily as man in equivalent
circumstances. Other mammals, such as gazelles, obtain most of
their required water supply from the vegetation they eat and live
in areas where there is no open water. Smaller animals, including
rodents, conserve their moisture by burrowing underground away
from the direct heat of the sun, only emerging for foraging at
night. All these living things have adapted to the environment
over a period of thousands of years; however, man has not made
this adaptation and must carry his food and water with him and
must also adapt to this severe environment.
Dogs are often found near mess facilities and
tend to be in packs of 8 or 10. Dogs are carriers of rabies and
should be avoided. Commanders must decide how to deal with packs
of dogs; extermination and avoidance are two options. Dogs also
carry fleas which may be transferred upon bodily contact. Rabies
is present in most desert mammal populations. Do not take any
chances of contracting fleas or rabies from any animal by adopting
Rats are carriers of various parasites and gastrointestinal
diseases due to their presence in unsanitary locations.
There is no reason to fear the desert environment,
and it should not adversely affect the morale of a soldier/marine
who is prepared for it. Lack of natural concealment has been known
to induce temporary agoraphobia (fear of open spaces) in some
troops new to desert conditions, but this fear normally disappears
with acclimatization. Remember that there is nothing unique about
either living or fighting in deserts; native tribesmen have lived
in the Sahara for thousands of years. The British maintained a
field army and won a campaign in the Western Desert in World War
II at the far end of a 12,000-mile sea line of communication with
equipment considerably inferior to that in service now. The desert
is neutral, and affects both sides equally; the side whose personnel
are best prepared for desert operations has a distinct advantage.
The desert is fatiguing, both physically and
mentally. A high standard of discipline is essential, as a single
individual's lapse may cause serious damage to his unit or to
himself. Commanders must exercise a high level of leadership and
train their subordinate leaders to assume greater responsibilities
required by the wide dispersion of units common in desert warfare.
Soldiers/marines with good leaders are more apt to accept heavy
physical exertion and uncomfortable conditions. Every soldier/marine
must clearly understand why he is fighting in such harsh conditions
and should be kept informed of the operational situation. Ultimately,
however, the maintenance of discipline will depend on individual
Commanders must pay special attention to the
welfare of troops operating in the desert, as troops are unable
to find any "comforts" except those provided by the
command. Welfare is an essential factor in the maintenance of
morale in a harsh environment, especially to the inexperienced.
There is more to welfare than the provision of mail and clean
clothing. Troops must be kept healthy and physically fit; they
must have adequate, palatable, regular food, and be allowed periods
of rest and sleep. These things will not always be possible and
discomfort is inevitable, but if troops know that their commanders
are doing everything they can to make life tolerable, they will
more readily accept the extremes brought on by the environment.
The extreme heat of the desert can cause heat
exhaustion and heatstroke and puts troops at risk of degraded
performance. For optimum mental and physical performance, body
temperatures must be maintained within narrow limits. Thus, it
is important that the body lose the heat it gains during work.
The amount of heat accumulation in the human body depends upon
the amount of physical activity, level of hydration, and the state
of personal heat acclimatization. Unit leaders must monitor their
troops carefully for signs of heat distress and adjust schedules,
work rates, rest, and water consumption according to conditions.
Normally, several physical and physiological
mechanisms (e.g., convection and evaporation) assure transfer
of excess body heat to the air. But when air temperature is above
skin temperature (around 92 degrees Fahrenheit) the evaporation
of sweat is the only operative mechanism. Following the loss of
sweat, water must be consumed to replace the body's lost fluids.
If the body fluid lost through sweating is not replaced, dehydration
will follow. This will hamper heat dissipation and can lead to
heat illness. When humidity is high, evaporation of sweat is inhibited
and there is a greater risk of dehydration or heat stress. Consider
the following to help prevent dehydration:
- Heat, wind, and dry air combine to produce
a higher individual water requirement, primarily through loss
of body water as sweat. Sweat rates can be high even when the
skin looks and feels dry.
- Dehydration nullifies the benefits of heat
acclimatization and physical fitness, it increases the susceptibility
to heat injury, reduces the capacity to work, and decreases appetite
and alertness. A lack of alertness can indicate early stages of
- Thirst is not an adequate indicator of dehydration.
The soldier/marine will not sense when he is dehydrated and will
fail to replace body water losses, even when drinking water is
available. The universal experience in the desert is that troops
exhibit "voluntary dehydration" that is, they maintain
their hydration status at about 2 percent of body weight (1.5
quarts) below their ideal hydration status without any sense of
Chronic dehydration increases the incidence of
several medical problems: constipation (already an issue in any
field situation), piles (hemorrhoids), kidney stones, and urinary
infections. The likelihood of these problems occurring can be
reduced by enforcing mandatory drinking schedules.
Resting on hot sand will increase heat stress--the
more a body surface is in contact with the sand, the greater the
heat stress. Ground or sand in full sun is hot, usually 30-45
degrees hotter than the air, and may reach 150 degrees Fahrenheit
when the air temperature is 120 degrees Fahrenheit. Cooler sand
is just inches below the surface; a shaded trench will provide
a cool resting spot.
At the first evidence of heat illness, have the troops stop work, get into shade, and rehydrate. Early intervention is important. Soldiers/ marines who are not taken care of can become more serious casualties.
Acclimatization to heat is necessary to permit
the body to reach and maintain efficiency in its cooling process.
A period of approximately 2 weeks should be allowed for acclimatization,
with progressive increases in heat exposure and physical exertion.
Significant acclimatization can be attained in 4-5 days, but full
acclimatization takes 7-14 days, with 2-3 hours per day of exercise
in the heat. Gradually increase physical activity until full acclimatization
Acclimatization does not reduce, and may increase,
water requirements. Although this strengthens heat resistance,
there is no such thing as total protection against the debilitating
effects of heat. Situations may arise where it is not possible
for men to become fully acclimatized before being required to
do heavy labor. When this happens heavy activity should be limited
to cooler hours and troops should be allowed to rest frequently.
Check the weather daily. Day-to-day and region-to-region variations
in temperatures, wind, and humidity can be substantial.
Climatic stress on the human body in hot deserts
can be caused by any combination of air temperature, humidity,
air movement, and radiant heat. The body is also adversely affected
by such factors as lack of acclimatization, being overweight,
dehydration, alcohol consumption, lack of sleep, old age, and
The body maintains its optimum temperature of
98.6 degrees Fahrenheit by conduction/convection, radiation, and
evaporation (sweat). The most important of these in the daytime
desert is evaporation, as air temperature alone is probably already
above skin temperature. If, however, relative humidity is high,
air will not easily evaporate sweat and the cooling effect is
reduced. The following paragraphs describe the effects of radiant
light, wind, and sand on personnel in desert areas.
Radiant light comes from all directions. The
sun's rays, either direct or reflected off the ground, affect
the skin and can also produce eyestrain and temporarily impaired
vision. Not only does glare damage the eyes but it is very tiring;
therefore, dark glasses or goggles should be worn.
Overexposure to the sun can cause sunburn. Persons
with fair skin, freckled skin, ruddy complexions, or red hair
are more susceptible to sunburn than others, but all personnel
are susceptible to some degree. Personnel with darker complexions
can also sunburn. This is difficult to monitor due to skin pigmentation,
so leaders must be ever vigilant to watch for possible sunburn
victims. Sunburn is characterized by painful reddened skin, and
can result in blistering and lead to other forms of heat illness.
Soldier/marines should acquire a suntan in gradual
stages (preferably in the early morning or late afternoon) to
gain some protection against sunburn. They should not be permitted
to expose bare skin to the sun for longer than five minutes on
the first day, increasing exposure gradually at the rate of five
minutes per day. They should be fully clothed in loose garments
in all operational situations. This will also reduce sweat loss.
It is important to remember that--
- The sun is as dangerous on cloudy days as it
is on sunny days.
- Sunburn ointment is not designed to give complete
protection against excessive exposure.
- Sunbathing or dozing in the desert sun can
The wind can be as physically demanding as the
heat, burning the face, arms, and any exposed skin with blown
sand. Sand gets into eyes, nose, mouth, throat, lungs, ears, and
hair, and reaches every part of the body. Even speaking and listening
can be difficult. Continual exposure to blown sand is exhausting
and demoralizing. Technical work spaces that are protected from
dust and sand are likely to be very hot. Work/rest cycles and
enforced water consumption will be required.
The combination of wind and dust or sand can
cause extreme irritation to mucous membranes, chap the lips and
other exposed skin surfaces, and can cause nosebleed. Cracked,
chapped lips make eating difficult and cause communication problems.
Irritative conjunctivitis, caused when fine particles enter the
eyes, is a frequent complaint of vehicle crews, even those wearing
goggles. Lip balm and skin and eye ointments must be used by all
personnel. Constant wind noise is tiresome and increases soldier/marine
fatigue, thus affecting alertness.
When visibility is reduced by sandstorms to the
extent that military operations are impossible, soldiers/marines
should not be allowed to leave their group for any purpose unless
secured by lines for recovery.
The following are special considerations when
performing operations in dust or sand:
- Contact lenses are very difficult to maintain
in the dry dusty environment of the desert and should not be worn
except by military personnel operating in air conditioned environments,
under command guidance.
- Mucous membranes can be protected by breathing
through a wet face cloth, snuffing small amounts of water into
nostrils (native water is not safe for this purpose) or coating
the nostrils with a small amount of petroleum jelly. Lips should
be protected by lip balm.
- Moving vehicles create their own sandstorms and
troops traveling in open vehicles should be protected.
- Scarves and bandannas can be used to protect
the head and face.
- The face should be washed as often as possible. The eyelids should be cleaned daily.
BASIC HEAT INJURY PREVENTION
The temperature of the body is regulated within
very narrow limits. Too little salt causes heat cramps; too little
salt and insufficient water causes heat exhaustion. Heat exhaustion
will cause a general collapse of the body's cooling mechanism.
This condition is heatstroke, and is potentially fatal. To avoid
these illnesses, troops should maintain their physical fitness
by eating adequately, drinking sufficient water, and consuming
adequate salt. If soldiers/marines expend more calories than they
take in, they will be more prone to heat illnesses. Since troops
may lose their desire for food in hot climates, they must be encouraged
to eat, with the heavier meal of the day scheduled during the
It is necessary to recognize heat stress symptoms
quickly. When suffering from heatstroke, the most dangerous condition,
there is a tendency for a soldier/marine to creep away from his
comrades and attempt to hide in a shady and secluded spot; if
not found and treated, he will die. When shade is required during
the day, it can best be provided by tarpaulins or camouflage nets,
preferably doubled to allow air circulation between layers and
dampened with any surplus water.
Approximately 75 percent of the human body is
fluid. All chemical activities in the body occur in a water solution,
which assists in the removal of toxic body wastes and plays a
vital part in the maintenance of an even body temperature. A loss
of 2 quarts of body fluid (2.5 percent of body weight) decreases
efficiency by 25 percent and a loss of fluid equal to 15 percent
of body weight is usually fatal. The following are some considerations
when operating in a desert environment:
- Consider water a tactical weapon. Reduce heat
injury by forcing water consumption. Soldiers/marines in armored
vehicles, MOPP gear, and in body armor need to increase their
- When possible, drink Cool (50-55 degrees Fahrenheit) water.
- Drink one quart of water in the morning, at
each meal, and before strenuous work. In hot climates drink at
least one quart of water each hour. At higher temperatures hourly
water requirements increase to over two quarts.
- Take frequent drinks since they are more often
effective than drinking the same amount all at once. Larger soldiers/marines
need more water.
- Replace salt loss through eating meals.
- When possible, work loads and/or duration of
physical activity should be less during the first days of exposure
to heat, and then should gradually be increased to follow acclimatization.
- Modify activities when conditions that increase
the risk of heat injury (fatigue/loss of sleep, previous heat
exhaustion, taking medication) are present.
- Take frequent rest periods in the shade, if
possible. Lower the work rate and work loads as the heat condition
- Perform heavy work in the cooler hours of the
day such as early morning or late evening, if possible.
A description of the symptoms and treatment for
heat illnesses follows:
- Heat cramps.
- Symptoms: Muscle cramps of arms, legs, and/or
stomach. Heavy sweating (wet skin) and extreme thirst.
- First aid: Move soldier/marine to a shady area and loosen clothing. Slowly give large amounts of cool water. Watch the soldier/marine and continue to give him water, if he accepts it. Get medical help if cramps continue.
- Heat exhaustion.
- Symptoms: Heavy sweating with pale, moist,
cool skin; headache, weakness, dizziness, and/or loss of appetite;
heat cramps, nausea (with or without vomiting), rapid breathing,
confusion, and tingling of the hands and/or feet.
- First aid: Move the soldier/marine to a cool, shady area and loosen/remove clothing. Pour water on the soldier/marine and fan him to increase the cooling effect. Have the soldier/ marine slowly drink at least one full canteen of water. Elevate the soldier's/marine's legs. Get medical help if symptoms continue; watch the soldier/marine until the symptoms are gone or medical aid arrives.
- Symptoms: Sweating stops (red, flushed, hot
- First aid: Evacuate to a medical facility immediately. Move the soldier/marine to a cool, shady area and loosen or remove clothing if the situation permits. Start cooling him immediately. Immerse him in water and fan him. Massage his extremities and skin and elevate his legs. If conscious, have the soldier/marine slowly drink one full canteen of water.
Maintaining safe, clean, water supplies is critical.
The best containers for small quantities of water (5 gallons)
are plastic water cans or coolers. Water in plastic cans will
be good for up to 72 hours; storage in metal containers is safe
only for 24 hours. Water trailers, if kept cool, will keep water
fresh up to five days. If the air temperature exceeds 100 degrees
Fahrenheit, the water temperature must be monitored. When the
temperature exceeds 92 degrees Fahrenheit, the water should be
changed, as bacteria will multiply. If the water is not changed
the water can become a source of sickness, such as diarrhea. Ice
in containers keeps water cool. If ice is put in water trailers,
the ice must be removed prior to moving the trailer to prevent
damage to the inner lining of the trailer.
Potable drinking water is the single most important
need in the desert. Ensure nonpotable water is never mistaken
for drinking water. Water that is not fit to drink but is not
otherwise dangerous (it may be merely oversalinated) may be used
to aid cooling. It can be used to wet clothing, for example, so
the body does not use too much of its internal store of water.
Use only government-issued water containers for
drinking water. Carry enough water on a vehicle to last the crew
until the next planned resupply. It is wise to provide a small
reserve. Carry water containers in positions that--
- Prevent vibration by clamping them firmly to
the vehicle body.
- Are in the shade and benefit from an air draft.
- Are protected from puncture by shell splinters.
- Are easily dismounted in case of vehicle evacuation.
Troops must be trained not to waste water. Water
that has been used for washing socks, for example, is perfectly
adequate for a vehicle cooling system.
Obtain drinking water only from approved sources
to avoid disease or water that may have been deliberately polluted.
Be careful to guard against pollution of water sources. If rationing
is in effect, water should be issued under the close supervision
of officers and noncommissioned officers.
Humans cannot perform to maximum efficiency on
a decreased water intake. An acclimatized soldier/marine will
need as much (if not more) water as the nonacclimatized soldier/marine,
as he sweats more readily. If the ration water is not sufficient,
there is no alternative but to reduce physical activity or restrict
it to the cooler parts of the day.
In very hot conditions it is better to drink
smaller quantities of water often rather than large quantities
occasionally. Drinking large quantities causes excessive sweating
and may induce heat cramps. Use of alcohol lessens resistance
to heat due to its dehydrating effect. As activities increase
or conditions become more severe, increase water intake accordingly.
The optimum water drinking temperature is between
10 degrees Celsius and 15.5 degrees Celsius (50-60 degrees Fahrenheit).
Use lister bags or even wet cloth around metal containers to help
Units performing heavy activities on a sustained
basis, such as a forced march or digging in, at 80 degrees wet
bulb globe temperature index, may require more than 3 gallons
of drinking water per man. Any increase in the heat stress will
increase this need. In high temperatures, the average soldier/marine
will require 9 quarts of water per day to survive, but 5 gallons
are recommended. Details on water consumption and planning factors
are contained in Appendix G.
While working in high desert temperatures, a
man at rest may lose as much as a pint of water per hour from
sweating. In very high temperatures and low humidity, sweating
is not noticeable as it evaporates so fast the skin will appear
dry. Whenever possible, sweat should be retained on the skin to
improve the cooling process; however, the only way to do this
is to avoid direct sun on the skin. This is the most important
reason why desert troops must remain fully clothed. If a soldier/marine
is working, his water loss through sweating (and subsequent requirement
for replenishment) increases in proportion to the amount of work
done (movement). Troops will not always drink their required amount
of liquid readily and will need to be encouraged or ordered to
drink more than they think is necessary as the sensation of thirst
is not felt until there is a body deficit of 1 to 2 quarts of
water. This is particularly true during the period of acclimatization.
Packets of artificial fruit flavoring encourages consumption due
to the variety of pleasant tastes.
All unit leaders must understand the critical
importance of maintaining the proper hydration status. Almost
any contingency of military operations will act to interfere with
the maintenance of hydration. Urine provides the best indicator
of proper hydration. The following are considerations for proper
hydration during desert operations:
- Water is the key to your health and survival.
Drink before you become thirsty and drink often, When you become
thirsty you will be about a "quart and a half low".
- Carry as much water as possible when away from
approved sources of drinking water. Man can live longer without
food than without water.
- Drink before you work; carry water in your belly,
do not "save" it in your canteen. Learn to drink a quart
or more of water at one time and drink frequently to replace sweat
- Ensure troops have at least one canteen of water
in reserve, and know where and when water resupply will be available.
- Carbohydrate/electrolyte beverages (e.g., Gatorade)
are not required, and if used, should not be the only source of
water. They are too concentrated to be used alone. Many athletes
prefer to dilute these 1:1 with water. Gaseous drinks, sodas,
beer, and milk are not good substitutes for water because of their
- If urine is more colored than diluted lemonade,
or the last urination cannot be remembered, there is probably
insufficient water intake. Collect urine samples in field expedient
containers and spot check the color as a guide to ensuring proper
hydration. Very dark urine warns of dehydration. Soldiers/marines should observe their own urine, and use the buddy system to watch
for signs of dehydration in others.
- Diseases, especially diarrheal diseases, will
complicate and often prevent maintenance of proper hydration.
Salt, in correct proportions, is vital to the
human body; however, the more a man sweats, the more salt he loses.
The issue ration has enough salt for a soldier/marine drinking
up to 4 quarts of water per day. Unacclimatized troops need additional
salt during their first few days of exposure and all soldiers/marines
need additional salt when sweating heavily. If the water demand
to balance sweat loss rises, extra salt must be taken under medical
direction. Salt, in excess of body requirements, may cause increased
thirst and a feeling of sickness, and can be dangerous. Water
must be tested before adding salt as some sources are already
saline, especially those close to the sea.
The desert can be combine to produce dangerously
cold. The dry air, wind, and clear sky can bone-chilling discomfort
and even injury. The ability of the body to maintain body temperature
within a narrow range is as important in the cold as in the heat.
Loss of body heat to the environment can lead to cold injury;
a general lowering of the body temperature can result in hypothermia,
and local freezing of body tissues can lead to frostbite. Hypothermia
is the major threat from the cold in the desert, but frostbite
Troops must have enough clothing and shelter
to keep warm. Remember, wood is difficult to find; any that is
available is probably already in use. Troops maybe tempted to
leave clothing and equipment behind that seems unnecessary (and
burdensome) during the heat of the day. Cold-wet injuries (immersion
foot or trench foot) may be a problem for dismounted troops operating
in the coastal marshes of the Persian Gulf during the winter.
Some guidelines to follow when operating in the cold are--
- Anticipate an increased risk of cold-wet injuries
if a proposed operation includes lowland or marshes. Prolonged
exposure of the feet in cold water causes immersion foot injury,
which is completely disabling.
- Check the weather-know what conditions you
will be confronting. The daytime temperature is no guide to the
nighttime temperature; 90-degree-Fahrenheit days can turn into
- The effects of the wind on the perception of
cold is well known. Windchill charts contained in FM 21-10 allow
estimation of the combined cooling power of air temperature and
wind speed compared to the effects of an equally cooling still-air
Uniforms should be worn to protect against sunlight
and wind. Wear the uniform loosely. Use hats, goggles, and sunscreen.
Standard lightweight clothing is suitable for desert operations
but should be camouflaged in desert colors, not green. Wear nonstarched
long-sleeved shirts, and full-length trousers tucked into combat
boots. Wear a scarf or triangular bandanna loosely around the
neck (as a sweat rag) to protect the face and neck during sandstorms
against the sand and the sun. In extremely hot and dry conditions
a wet sweat rag worn loosely around the neck will assist in body
Combat boots wear out quickly in desert terrain,
especially if the terrain is rocky. The leather drys out and cracks
unless a nongreasy mixture such as saddle soap is applied. Covering
the ventilation holes on jungle boots with glue or epoxies prevents
excessive sand from entering the boots. Although difficult to
do, keep clothing relatively clean by washing in any surplus water
that is available. When water is not available, air and sun clothing
to help kill bacteria.
Change socks when they become wet. Prolonged
wear of wet socks can lead to foot injury. Although dry desert
air promotes evaporation of water from exposed clothing and may
actually promote cooling, sweat tends to accumulate in boots.
Soldier/marines may tend to stay in thin clothing
until too late in the desert day and become susceptible to chills--so
respiratory infections may be common. Personnel should gradually
add layers of clothing at night (such as sweaters), and gradually
remove them in the morning. Where the danger of cold weather injury
exists in the desert, commanders must guard against attempts by
inexperienced troops to discard cold weather clothing during the
heat of the day.
Compared to the desert battle dress uniform (DBDU)
the relative impermeability of the battle dress overgarment (BDO)
reduces evaporative cooling capacity. Wearing underwear and the
complete DBDU, with sleeves rolled down and under the chemical
protective garment, provides additional protection against chemical
poisoning. However, this also increases the likelihood of heat
HYGIENE AND SANITATION
Personal hygiene is absolutely critical to sustaining
physical fitness. Take every opportunity to wash. Poor personal
hygiene and lack of attention to siting of latrines cause more
casualties than actual combat. Field Marshal Rommel lost over
28,400 soldiers of his Afrika Corps to disease in 1942. During
the desert campaigns of 1942, for every one combat injury, there
were three hospitalized for disease. Hygiene and sanitation are
covered in detail in FM 21-10. This section highlights some of
the points that are of special importance to the commander in
Proper standards of personal hygiene must be
maintained not only as a deterrent to disease but as a reinforcement
to discipline and morale. If water is available, shave and bathe
daily. Cleaning the areas of the body that sweat heavily is especially
important; change underwear and socks frequently, and use foot
powder often. Units deployed in remote desert areas must have
a means of cutting hair therefore, barber kits should be maintained
and inventoried prior to any deployment. If sufficient water is
not available, troops should clean themselves with sponge baths,
solution-impregnated pads, a damp rag, or even a dry, clean cloth.
Ensure that waste water is disposed of in an approved area to
prevent insect infestation. If sufficient water is not available
for washing, a field expedient alternative is powder baths, that
is, using talcum or baby powder to dry bathe.
Check troops for any sign of injury, no matter
how slight, as dirt or insects can cause infection in minor cuts
and scratches. Small quantities of disinfectant in washing water
reduces the chance of infection. Minor sickness can have serious
effects in the desert. Prickly heat for example, upsets the sweating
mechanism and diarrhea increases water loss, making the soldier/marine
more prone to heat illnesses. The buddy system helps to ensure
that prompt attention is given to these problems before they incapacitate
Intestinal diseases can easily increase in the
desert. Proper mess sanitation is essential. Site latrines well
away and downwind of troop areas and lagers. Trench-type latrines
should be used where the soil is suitable but must be dug deeply,
as shallow latrines become exposed in areas of shifting sand.
Funnels dug into a sump work well as urinals. Layer the bottom
of slit trenches with lime and cover the top prior to being filled
in. Ensure lime is available after each use of the latrine. Flies
area perpetual source of irritation and carry infections. Only
good sanitation can keep the fly problem to a minimum. Avoid all
local tribe camps since they are frequently a source of disease
Diseases common to the desert include plague,
typhus, malaria, dengue fever, dysentery, cholera, and typhoid.
Diseases which adversely impact hydration, such as those which
include nausea, vomiting, and diarrhea among their symptoms, can
act to dramatically increase the risk of heat (and cold) illness
or injury. Infectious diseases can result in a fever; this may
make it difficult to diagnose heat illness. Occurrences of heat
illness in troops suffering from other diseases complicate recovery
from both ailments.
Many native desert animals and plants are hazardous.
In addition to injuries as a result of bites, these natural inhabitants
of the desert can be a source of infectious diseases.
Many desert plants and shrubs have a toxic resin
that can cause blisters, or spines that can cause infection. Consider
milky sap, all red beans, and smoke from burning oleander shrubs,
poisonous. Poisonous snakes, scorpions, and spiders are common
in all deserts. Coastal waters of the Persian Gulf contain hazardous
marine animals including sea snakes, poisonous jellyfish, and
Skin diseases can result from polluted water
so untreated water should not be used for washing clothes; although
it can be used for vehicle cooling systems or vehicle decontamination.
The excessive sweating common in hot climates
brings on prickly heat and some forms of fungus infections of
the skin. The higher the humidity, the greater the possibility
of their occurrence. Although many deserts are not humid, there
are exceptions, and these ailments are common to humid conditions.
The following are additional health-related considerations
when operating in a desert environment:
- The most common and significant diseases in
deserts include diarrheal and insectborne febrile (i.e., fever
causing) illnesses-both types of these diseases are preventable.
- Most diarrheal diseases result from ingestion
of water or food contaminated with feces. Flies, mosquitoes, and
other insects carry fever-causing illnesses such as malaria, sand
fly fever, dengue (fever with severe pain in the joints), typhus,
and tick fevers.
- There are no safe natural water sources in
the desert. Standing water is usually infectious or too brackish
to be safe for consumption. Units and troops must always know
where and how to get safe drinking water.
- Avoid brackish water (i.e., salty). It, like
sea water, increases thirst; it also dehydrates the soldier/marine
faster than were no water consumed. Brackish water is common even
in public water supplies, Iodine tablets only kill germs, they
do not reduce brackishness.
- Water supplies with insufficient chlorine residuals,
native food and drink, and ice from all sources are common sources
of infective organisms.
Both diarrheal and insectborne diseases can be
prevented through a strategy which breaks the chain of transmission
from infected sources to susceptible soldiers/marines by effectively
applying the preventive measures contained in FM 21-10. Additional
preventive measures are described below:
- Careful storage, handling and purification/preparation
of water and food are the keys to prevention of diarrheal disease. Procure all food, water, ice, and beverages from US military approved
sources and inspect them routinely.
- Well-cooked foods that are "steaming hot"
when eaten are generally safe, as are peeled fruits and vegetables.
- Local dairy products and raw leafy vegetables
are generally unsafe.
- Consider the food in native markets hazardous.
Avoid local food unless approved by medical personnel officials.
- Assume raw ice and native water to be contaminated--raw
ice cannot be properly disinfected. Ice has been a major source
of illness in all prior conflicts; therefore, use ice only from
- If any uncertainty exists concerning the quality
of drinking water, troops should disinfect their supplies using
approved field-expedient methods (e.g., hypochlorite for lister
bags, iodine tablets for canteens, boiling).
- Untreated water used for washing or bathing
- Hand washing facilities should be established
at both latrines and mess facilities. Particular attention should
be given to the cleanliness of hands and fingernails. Dirty hands
are the primary means of transmitting disease.
- Dispose of human waste and garbage as specified
in FM 21-10. Additional considerations regarding human waste and
- Sanitary disposal is important in preventing
the spread of disease from insects, animals, and infected individuals,
to healthy soldiers/marines.
- Construction and maintenance of sanitary latrines are essential.
- Burning is the best solution for waste.
- Trench latrines can be used if the ground is suitable, but they must be dug deeply enough so that they are not exposed to shifting sand, and they must have protection against flies and other insects that can use them as breeding places.
- Food and garbage attract animals--do not sleep where you eat and keep refuse areas away from living areas.
- Survey the unit area for potential animal hazards.
- Shake out boots, clothing, and bedding before
Conditions in an arid environment can damage
military equipment and facilities. Temperatures and dryness are
major causes of equipment failure, and wind action lifts and spreads
sand and dust, clogging and jamming anything that has moving parts.
Vehicles, aircraft, sensors, and weapons are all affected. Rubber
components such as gaskets and seals become brittle, and oil leaks
are more frequent. Ten characteristics of the desert environment
may adversely affect equipment used in the desert:
- Dust and sand.
- Temperature variations.
- Thermal bending.
- Optical path bending.
- Static electricity.
- Radiant light.
The relative importance of each characteristic
varies from desert to desert. Humidity, for example, can be discounted
in most deserts but is important in the Persian Gulf.
Terrain varies from nearly flat, with high trafficability,
to lava beds and salt marshes with little or no trafficability.
Drivers must be well trained in judging terrain over which they
are driving so they can select the best method of overcoming the
varying conditions they will encounter. Techniques for driving
and operating equipment in desert conditions are contained in
Track vehicles are well suited for desert operations.
Wheel vehicles may be acceptable as they can go many places that
track vehicles can go; however, their lower speed average in poor
terrain maybe unacceptable during some operations. Vehicles should
be equipped with extra fan belts, tires, (and other items apt
to malfunction), tow ropes (if not equipped with a winch), extra
water cans, and desert camouflage nets. Air-recognition panels,
signal mirrors, and a tarpaulin for crew sun protection are very
useful. Wheel vehicles should also carry mats, or channels as
appropriate, to assist in freeing mired vehicles.
The harsh environment requires a very high standard
of maintenance, which may have to be performed well away from
specialized support personnel. Operators must be fully trained
in operating and maintaining their equipment. Some types of terrain
can have a severe effect on suspension and transmission systems,
especially those of wheel vehicles. Tanks are prone to throw tracks
when traveling over rocks.
Track components require special care in the
desert. Grit, heat, and bad track tension accelerate track failure.
Sprockets wear out quickly in sandy conditions. Track pins break
more easily in high temperatures and high temperatures also increase
rubber/metal separation on road wheels. Proper track tension is
critical, as loose track is easily thrown and excessive tension
causes undue stress on track components.
Increase the unit PLL of tires and tracks as
sand temperatures of 165 degrees Fahrenheit are extremely detrimental
to rubber, and weaken resistance to sharp rocks and plant spines,
Items affected by mileage such as wheels, steering, track wedge
bolts and sprocket nuts, and transmission shafts, must be checked
for undue wear when conducting before-, during-, and after-operations
Vehicle coding and lubrication systems are interdependent.
A malfunction by one will rapidly place the other system under
severe strain. In temperature extremes, all types of engines are
apt to operate above optimum temperatures, leading to excessive
wear, or leaking oil seals in the power packs, and ultimately,
engine failure. Commanders should be aware which types of vehicles
are prone to excessive overheating, and ensure extra care is applied
to their maintenance. The following are considerations for ensuring
engines do not overheat:
- Check oil levels frequently to ensure proper
levels are maintained (too high may be as bad as too low), that
seals are not leaking, and oil consumption is not higher than
- Keep radiators and air flow areas around engines
clean and free of debris and other obstructions.
- Fit water-cooled engines with condensers to
avoid steam escaping through the overflow pipe.
- Cooling hoses must be kept tight (a drip a
second loses 7 gallons of fluid in 24 hours).
- Operators should not remove hood side panels
from engine compartments while the engine is running as this causes
air turbulence and leads to ineffective cooling.
Batteries do not hold their charge efficiently
in intense heat. Check them twice daily. The following are additional
considerations for maintaining batteries in intense heat:
- Change battery specific gravity to adjust to
the desert environment (see vehicle TMs for details).
- Keep batteries full, but not overfilled, and
carry a reserve of distilled water.
- Keep air vents clean, or vapors may build up
pressure and cause the battery to explode.
- Set voltage regulators as low as practical.
- Increase dry battery supplies to offset high
attrition rate caused by heat exposure.
Severe heat increases pressure in closed pressurized
systems such as the M2 fire burner unit, and increases the volume
of liquids. Ensure that the working pressure of all equipment
is within safety limits and be careful when removing items such
as filler caps.
Treat Halon fire extinguishers with care. High temperatures may cause them to discharge spontaneously. Put wet rags on them during the hottest part of the day to keep them cooler.
Some items of equipment are fitted with thermal
cutouts that open circuit breakers whenever equipment begins to
overheat. Overheating is often caused by high ambient temperatures,
and can be partly avoided by keeping the item in the shade or
wrapping it in a wet cloth to maintain a lower temperature by
Flying time and performance of helicopters are
degraded as the altitude and heat increases. Helicopter performance
is also affected by humidity. Aircraft canopies have been known
to bubble under direct heat and should be covered when not in
Ammunition must be out of direct heat and sunlight.
Use camouflage nets and tarpaulins to provide cover. Ammunition
cool enough to be held by bare hands is safe to fire.
Wood shrinks in a high-temperature, low-humidity
environment. Equipment, such as axes carried on track vehicles,
can become safety hazards as heads are likely to fly off shrunken
Radiators require special attention. Proper cooling-system operation is critical in high-temperature environments. Check cooling systems for serviceability prior to deployment. Local water maybe high in mineral content which will calcify in cooling systems. Distilled water is better since tap water contains chemicals that will form a crusty coating inside the radiator and will ultimately clog it. A mixture of 40 percent antifreeze and 60 percent water is usually acceptable--check your appropriate technical manual to be certain.
During movement, and at operation sites where
extremely hot temperatures exist, continuous protection from the
heat is necessary for medical items and supplies, which deteriorate
Air and all fluids expand and contract according
to temperature. If tires are inflated to correct pressure during
the cool of night, they may burst during the heat of day. If fuel
tanks are filled to the brim at night, they will overflow at midday.
Servicing these items during the heat of day can result in low
tire pressure, overheating of tires, and a lack of endurance if
the fuel tanks were not filled to their correct levels. Air pressure
in tires must be checked when the equipment is operating at efficient
working temperatures, and fuel tanks must be filled to their correct
capacity as defined in the appropriate technical manual. These
items should be checked several times a day and again at night.
The major problem with radios in a desert environment
is overheating. The following steps can help prevent overheating
- Keep radios out of direct sunlight.
- Place a piece of wood on top of the radio.
Leaving space between the wood and the top of the radio will help
cool the equipment. Operating on low power whenever possible will
- Place wet rags on top of radios to help keep
them cool and operational. Do not cover the vents.
Any oil or fuel blown onto a cooler (heat exchanger)
will gather and quickly degrade cooling. Fix even slight leaks
promptly. Do not remove cooling ducts or shrouds. Check them for
complete coverage--use tape to seal cracks. Do not remove serviceable
thermostats if overheating occurs.
Desert winds, by their velocity alone, can be
very destructive to large and relatively light materiel such as
aircraft, tentage, and antenna systems. To minimize the possibility
of wind damage, materiel should be sited to benefit from wind
protection and should be firmly picketed to the ground.
DUST AND SAND
Dust and sand are probably the greatest danger
to the efficient functioning of equipment in the desert. It is
almost impossible to avoid particles settling on moving parts
and acting as an abrasive. Sand mixed with oil forms an abrasive
Lubricants must be of the correct viscosity for
the temperature and kept to the recommended absolute minimum in
the case of exposed or semiexposed moving parts. Lubrication fittings
are critical items and should be checked frequently. If they are
missing, sand will enter the housing causing bearing failure.
Teflon bearings require constant inspection to ensure that the
coating is not being eroded.
Proper lubrication is crucial for success. Wipe
off all grease fittings before you attach the grease gun and after
use. Keep cans of grease covered to prevent sand contamination.
Preserve opened grease containers by covering and sealing with
plastic bags. Use of grease cartridges in lieu of bulk grease
is preferred. All POL dispensing tools must be stored in protected
areas to prevent contamination. Place a tarpaulin, or other material,
under equipment being repaired to prevent tools and components
from being lost in the sand. The automotive-artillery grease possesses
a significantly high-temperature capability. If not available,
an alternative is general purpose wide-temperature range (WTR)
Oil should be changed about twice as often under
desert conditions as under US or European conditions, not only
because grit accumulates in the oil pan, but also because noncombusted
low-octane fuel seeps down the cylinder walls and dilutes the
reservoir. Diluted lubricants cool less effectively, and evaporate
at the higher temperatures generated during engine operation.
Oil changes and lubrication of undercarriage points at more frequent
intervals will prolong engine and vehicle life under desert conditions.
Units employed in desert environments should reevaluate their
engine oil requirements and plan accordingly.
Keeping sand out of maintenance areas is critical
due to the strong possibility of sand or dust entering the cylinders
or other moving parts when the equipment is stripped. Baggies,
cloth, or plastic can be used to protect open or disassembled
components from blowing sand and dust. The same applies for disconnected
water, oil, or other fluid lines. Be sure to cover both ends of
the connection if stored. It is essential to have screens against
blowing sand (which also provides shade for mechanics). The surrounding
ground may be soaked in used oil or covered with rocks to bind
it down. Mechanics must keep their tools clean.
Dust and sand can easily cause failure of such
items as radio and signal distribution panels, and circuit breakers,
and cause small electrical motors to burn out. Wheel and flight
control bearings may require daily cleaning and repacking, and
engines should be flushed of contaminants daily.
Rotor heads have reduced life, requiring more
frequent inspections than in temperate climates. Pay particular
attention to sand-caused wear on rotor heads, leading edges of
rotor blades, and exposed flight controls. Over 200 pounds of
dirt has been known to accumulate in the fuselage area of helicopters
operating in desert conditions. These areas must be routinely
checked and cleaned to prevent a pound-for-pound reduction in
Filters must be used when refueling any type
of vehicle, and the gap between the nozzle and the fuel tank filler
pipe must be kept covered. It takes comparatively little dirt
to block a fuel line. Fuel filters will require more frequent
cleaning and will need to be checked and replaced often. Engine
oil should be changed more often and oil filters replaced more
frequently than in temperate climates.
Compression-ignition engines depend on clean
air; therefore, examine and clean air cleaners of every type of
equipment at frequent intervals. The exact interval depends on
the operating conditions, but as a minimum, should be checked
at least daily.
Air compressors are valuable pieces of equipment
in the desert. They are essential for cleaning air filters and
removing dust and sand from components. Intake filters require
Windblown sand and grit, in addition to heat,
will damage electrical wire insulation over a period of time.
All cables that are likely to be damaged should be protected with
tape before insulation becomes worn. Sand will also find its way
into parts of items such as "spaghetti cord" plugs,
either preventing electrical contact or making it impossible to
join the plugs together. Use a brush, such as an old toothbrush,
to brush out such items before they are joined. Electrical tape
placed over the ends of spaghetti cords also works.
Radio is the primary means of communications
in the desert. It can be employed effectively in desert climates
and terrain to provide the reliable communications demanded by
widely dispersed forces. However, desert terrain provides poor
electrical ground, and a counterpoise (an artificial ground) is
needed to improve the range of certain antennas.
Some receiver-transmitters have ventilating ports
and channels that can get clogged with dust. These must be checked
regularly and kept clean to prevent overheating. Mobile subscriber
equipment may require the deployment of additional radio access
units (RAU) AN/VRC-191. These assemblages are the primary link
for the mobile subscriber radio telephone terminal (MSRT) AN/VRC-97s
which are located down to battalion level. The normal operating
range of the receiver-transmitter used with these radios may only
be 10 kilometers in the desert.
Dust and sand adversely affect the performance
of weapons. Weapons may jam or missiles lock on launching rails
due to sand and dust accumulation. Sand- or dust-clogged barrels
lead to in-bore detonations. Daily supervised cleaning of weapons
is essential. Particular attention should be given to magazines
which are often clogged, interrupting the feeding of weapons.
Cover missiles on launchers until required for use. To avoid jamming
due to the accumulation of sand, the working parts of weapons
must have the absolute minimum amount of lubrication. It may even
be preferable to have them totally dry, as any damage caused during
firing will be less than that produced by the sand/oil abrasive
paste. Paintbrushes are among the most useful tools to bring to
the desert; they are extremely effective in cleaning weapons and
Take precautions to prevent exposure of floppy
disks and computers to dust or sand. Covering them in plastic
bags is a technique that has worked for several different units.
A number of units have successfully operated PLL computers in
inflatable medical NBC shelters (MIS 1). This technique has obvious
drawbacks since the shelter was not designed for this; however,
until a materiel fix is developed, this sort of innovation may
be necessary. Compressed air cans, locally purchased from computer
vendors, will facilitate the cleaning of keyboards and other components
of computer systems.
All optics are affected by blown sand, which
gradually degrade their performance due to small pitting and scratching.
It is necessary to guard against buildup of dust on optics, which
may not be apparent until the low light optical performance has
severely deteriorated. It may be advisable to keep optics covered
with some form of cellophane film until operations are about to
start, especially if the unit is in a sandstorm. A cover that
has no sand on the underside should also be used and must be secured
so it cannot vibrate against the wind screen. Both of these measures
are equally important to tactical security as sun reflected from
these optics will reveal positions.
Sand and dirt can easily accumulate in hull bottoms
of armored vehicles. This accumulation, combined with condensation
or oil, can cause jamming of control linkages. Sand accumulation
at the air-bleeder valve can inhibit heat from escaping from the
transmission and result in damage to the transmission. Park tactical
wheeled vehicles with the rear facing the wind to keep sand out
of the radiator. Tracked vehicles should park to protect the engine
compartment (grille doors away from wind) from the same sort of
damage. The operator's checks and services increase in importance
in this environment.
Some deserts are humid. Where this is the case,
humidity plus heat encourages rust on bare metal and mold in enclosed
spaces such as optics. Bare metal surfaces on equipment not required
for immediate use must be kept clean and very lightly lubricated.
Items such as optics must be stored in dry conditions;
those in use should be kept where air can circulate around them,
and should be purged at frequent intervals. Aircraft must be washed
daily, particularly if there is salt in the air, using low-pressure
In deserts with relatively high-dew levels and
high humidity, overnight condensation can occur wherever surfaces
(such as metal exposed to air) are cooler than the air temperature.
Condensation can affect such items as optics, fuel lines, and
air tanks. Drain fuel lines both at night and in the morning (whenever
necessary). Clean optics and weapons frequently. Weapons, even
if not lubricated, accumulate sand and dirt due to condensation.
Weapon systems such as the tank cannon are affected
in several ways by the desert. One is thermal bending, which is
the uneven heating and cooling of a gun tube due to ambient temperature
changes. Modem tanks, like the Ml, have been designed to compensate
for these factors. The muzzle reference system (MRS) allows the
crew to monitor any loss of gun sight relationship and to comet
for any error using the MRS update at regular intervals. Ml-series
tanks are equipped with a thermal shroud, allowing for more even
heating and cooling of the gun tube. Both factors can greatly
reduce the accuracy of a tank weapon system. By boresighting at
regular intervals and constant monitoring of the fire control
system, the tank crew can maximize its readiness. "Gun tube
droop" can be countered using the MRS update at least four
times in a 24-hour period: at dawn as part of stand-to; at noon
to compensate for gun tube temperature chang: before EENT, for
TIS reticle confirmation; and at 0100 hours to compensate for
gun tube temperature changes.
OPTICAL PATH BENDING
The apparent illusion of target displacement
is commonly called refraction. Under certain light and environmental
conditions, the path of light (line of sight) may not appear to
travel in a straight line. Refraction may cause problems for tank
crews attempting engagements at ranges beyond 1,500 meters. Figure 1-17 shows an example of optical path bending in the desert. Refraction
may occur in the following conditions:
Any time |
heat shimmer is
present, refraction may
The effect of refraction is to make the target
appear lower during the day; the sight picture, though it appears
center of visible mass to the gunner, is actually below the target.
This may result in a short round. At night, the effects are the
opposite and may result in an over round. Crews must not be fooled
by what appears to be a good range from their laser range finder
(LRF); the laser beam will refract with other light rays and still
hit the desired target.
The most effective measure available to the crew
to minimize refraction is an elevated firing position. A position
at least 10 meters above intervening terrain will generally negate
any effects. If this type of position is not available, a crew
operating under conditions favorable to refraction, and having
missed with their first round, should apply the following:
| NOTE:Crews do not |
need to make a
correction for refraction
at ranges of less
than 1,500 meters.
Boresight does not correct refraction, but crews
must ensure that all prepare-to-fire checks and boresighting procedures
are performed correctly. When a crew is missing targets under
these conditions, the cause is refraction and not crew error or
loss of boresight due to improper procedures.
Static electricity is prevalent and poses a danger
in the desert. It is caused by atmospheric conditions coupled
with an inability to ground out due to dryness of the terrain.
It is particularly prevalent with aircraft or vehicles having
no conductor contact with the soil. The difference of electrical
potential between separate materials may cause an electrical discharge
between them when contact is made, and if flammable gases are
present, they may explode and cause a fire. Poor grounding conditions
aggravate the problem. Be sure to tape all sharp edges (tips)
of antennas to reduce wind-caused static electricity. If you are
operating from a fixed position, ensure that equipment is properly
Establish a metal circuit between fuel tankers
and vehicles before and during refueling. Ensure the fuel tankers
and vehicles are grounded (for example, by a cable and picket
or by a crowbar). Grounding of vehicles and equipment should be
accomplished in accordance with appropriate operations manuals.
Static electricity is also a hazard with helicopter
sling loads. Exercise care when handling and transporting unlike
materials that might generate static electricity. Also turn off
all switches, uncouple electrical connectors, and ground vehicle
or aircraft electrically-operated weapon systems before reaming.
Static electricity will also ruin circuit boards and other electronic
Radiant light may be detrimental to plastics, lubricants, pressurized gases, some chemicals, and infrared tracking and guidance systems. Items like CO² fire extinguishers, M13 decontamination and reimpregnating kits, and Stinger missiles must be kept out of constant direct sunlight. Optics have been known to discolor under direct sunlight (although this is unusual), so it is wise to minimize their exposure to the sun's rays.
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