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LESSON ONE
CHARACTERISTICS, WEATHER INJURIES, AND
EFFECTS OF CHANGES WITHIN THE DESERT ENVIRONMENT
OVERVIEW
TASK DESCRIPTION:
In this lesson, you will learn to identify and select the characteristics of the desert in accordance with the key word "METT-T" (Mission, Enemy, Terrain, Troops and Time available). You will learn to identify and plan for special considerations in the prevention, identification, and treatment of hot and cold weather injuries in the desert. Also you will learn how to determine the effects of changes within the environment to include battlefield lights, noises and range estimation.
LEARNING OBJECTIVE:
| TASKS: | Identify and select the characteristics of the desert in accordance with the key word "METT-T" (Mission, Enemy, Terrain, Troops and Time available). Identify and plan for special considerations in the prevention, identification, and treatment of hot and cold weather injuries in the desert. Describe the effects of changes within the desert environment to include battlefield lights, noises and range estimation. |
| CONDITIONS: | You will be given information from FM 90-3, FM 21-76 and Newsletter No. 90-7, Special Edition, Aug 90. |
| STANDARDS: | Identify and select the characteristics of the desert in accordance with the key word "METT-T" (Mission, Enemy, Terrain, Troops and Time available), identify and plan for special considerations in the prevention, identification, and treatment of hot and cold weather injuries in the desert, and describe the effects of changes within the desert environment to include battlefield lights, noises and range estimation in accordance with FM 90-3, FM 21-76 and Newsletter No. 90-7, Special Edition, Aug 90. |
| REFERENCES: | The material contained in this lesson was derived from the following publications:
FM 90-3; FM 21-76 |
INTRODUCTION
The desert is harsh. It can easily kill an unprepared soldier. Besides making living conditions extremely uncomfortable, the desert can pose a constant challenge to every soldier. Each must be physically, mentally, and professionally prepared to meet that challenge. Survival in a desert, as in any area, depends upon your knowledge of the terrain and the basic climatic elements, your ability to cope with them, and your will to live.
This lesson describes the characteristics and changes of the desert's environment and its effects of hot and cold weather injuries.
You must understand the desert environment to prepare for desert operations, fight in the desert environment, and provide the combat service support required for successful desert operations.
1. Desert Environment.
Deserts are arid, barren regions of the earth incapable of supporting normal life due to lack of fresh water. Temperatures vary according to latitude and season. They range from over 136 degrees Fahrenheit (57.78 degrees Centigrade) in Mexico and Libya to the bitter cold of winter in the Gobi Desert in East Asia.
Figure 1-1 shows the desert areas of the world. In some deserts, the day to night temperatures vary as much as 70 degrees Fahrenheit.
Some animals and plants have adapted successfully to desert conditions where annual rainfall may vary from zero to 10 inches and is often unpredictable. Desert terrain and vegetation varies considerably from place to place, the sole common denominator being the LACK OF WATER. This environment can profoundly affect military operations.
You must realize that deserts are affected by seasons. Those in the Southern Hemisphere have a summer between 21 December and 21 March. This six-month difference from the United States is important when considering equipping, training and acclimatizing soldiers for desert operations south of the equator.
Figure 1-1. Desert Areas of the World
2. Desert Terrains.
There are three basic types of deserts: mountain, rocky plateau, and sandy or dune deserts. Besides their unique terrains, two other types of terrain, the salt marsh and the highly dissected terrain (called "gebel"), seem to blend into other types of terrain. These types of terrains will not only affect your ability to find water, food, and shelter, they will also
- make physical movement quite demanding.
- make land navigation difficult.
- limit cover and concealment.
a. Mountain. Mountain deserts are characterized by scattered ranges or areas of barren hills or mountains, separated by dry, flat basins, as shown in Figure 1-2. 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 rapidly as a flash flood. This erodes deep gullies and ravines and deposits sand and gravel around the edges of the basins. Water rapidly evaporates, leaving the land as barren as before, perhaps with short lived vegetation. If enough water enters the basin to offset the rate of evaporation, shallow lakes may develop, mostly with high-salt content. Examples are the Great Salt Lake in Utah or the Dead Sea in the Near East.
Mountain deserts at high altitudes have thin air and little or no vegetation. Sunburn is a danger. Climbing at high altitudes requires extra physical exertion and increases your need for water. Movement on mountains during darkness is extremely dangerous.
Figure 1-2. Mountain Desert - (Yemen) (Aden).
b. Rocky Plateau. Rocky plateau deserts have slight relief interspersed by extensive flat areas with quantities of solid or broken rock at or near the surface, as shown in Figure 1-3. The rocks often form natural cisterns that collect water after rains. Look closely for these areas. Sometimes animal or bird indicators, such as trails, droppings, or birds in flight, may point out water sources.
There may be sand dunes around the plateau and rock out croppings that offer shade as well as cover and concealment. Movement at night is dangerous.
You may find cut or dry, steep-walled eroded valleys, known as "wadis" in the Middle East and "arroyos" or "canyons" in the United States and Mexico. Their flat bottoms may be superficially attractive as assembly areas. However, the narrower of these valleys can be extremely dangerous to men and material due to flash flooding after rains. The Golan Heights is an example of rocky plateau desert.
Figure 1-3. Rocky Plateau Desert - The Golan Heights.
c. Sandy or Dune. Sandy or dune deserts are extensive flat areas covered with sand or gravel, the product of ancient deposits or modern wind erosion, as shown in Figure 1-4. "Flat" is relative in this case, as some areas may contain sand dunes that are more than 1,000 feet high and 10 to 15 miles long. Traffic conditions in such terrain will depend on windward/leeward gradients of the dunes and texture of sand. Other areas, however, may be flat for 3,000 meters and beyond. Plant life may vary from none to scrub reaching more than two meters high. Sand dune deserts include the ergs of the Sahara, The Sinai Desert, the Empty Quarter of the Arabian Desert, areas of California and New Mexico, and the Kalahari in South Africa. You should avoid travel through sand dune deserts if possible.
Figure 1-4. Dune Desert - Western Sahara.
d. Salt Marshes. Salt marshes are flat, desolate areas, sometimes studded with clumps of grass, but devoid of other vegetation. They are in arid areas where rainwater has collected, evaporated, and left large deposits of alkali salts. Any water is so salty it is undrinkable. A crust, which may be from two to 30 centimeters thick, forms over the saltwater. In arid areas there are salt marshes hundreds of kilometers square. These areas support many insects, most of which bite. Avoid salt marshes. These types of terrain are highly corrosive to boots, clothing, and skin.
e. Dissected Terrain (Gebel). You find highly dissected terrain in all arid areas. Rainstorms erode soft sand and carve out miniature canyons, sometimes called gebel or wadi. A wadi may range from three meters wide and two meters deep to several hundred meters wide and deep. The direction it takes varies as much as its width and depth, twisting and turning, forming a maze. You can easily become lost because of this maze-like pattern. A wadi will give you good cover and concealment, but you should not try to move through it.
3. Desert Driving Techniques.
a. Sand. A sandy desert may be nearly flat or broken up by dunes. The best time to drive on sand is at night or early morning when the sand is damp and traction is better. A surface crust, caused by chemicals cementing sand particles together, covers some areas. In some cases, it is possible to drive on this crust to keep the dust down. Use the following techniques when driving in sand.
(1) Before entering sand, you should select a gear that will allow the vehicle to keep as much torque as possible without causing the wheels to spin and to minimize changing gears.
(2) A lack of steering response in a tracked vehicle indicates that sand is building up between the rear sprockets and the treads. If you allow this to continue, the sand will build up and force the track off. You can throw the sand off by "shaking" the vehicle with the steering or by backing up. You must evenly distribute vehicle loads and use rear-wheel drive where necessary to avoid digging in the front wheels. Drivers should switch to all-wheel drive or change gears before a vehicle becomes bogged down.
(3) Crossing dunes requires careful reconnaissance. Normally, a crust that has a fairly gradual slope covers the upwind side of a dune. The downwind side will be steeper and have no crust. Before crossing a dune, you should climb it on foot, checking the
- crust thickness.
- angle of the crest to be sure that the vehicle will not become bellied up at the top.
- degree of slope and softness of the downwind side.
Once you're satisfied, you can drive the vehicle straight up the slope at best possible speed and crest the dune. Maintain a controlled descent on the other side.
b. Hillocks. Hillocks are little hills built up by the wind blowing sand around small shrubs. You should not drive wheeled vehicles through these areas without engineering assistance.
c. Thorns. Thorn bushes or cacti can cause frequent tire punctures. When operating in these areas, you need to increase the number of tires carried in your unit's PLL.
d. Rocks. Rock and boulder-strewn areas, including lava beds, can extend for miles. There are so many eroded and sharp-edged desert rocks, that it is almost impossible to avoid any but the largest. The harsh jolting will wear you out and severely wear tracks, wheels, springs and shock absorbers. Vehicles can follow one another in this type of terrain, and it may be possible to reconnoiter and mark a route. While crossing large rocks, drivers should try to get a rolling effect by braking as the wheels ride over a rock so the axle settles gently on the other side.
4. Climate and Weather Conditions.
In an arid area, there are some environmental factors you should consider.
a. Temperatures. The highest known ambient temperature recorded in deserts was 136.4 degrees Fahrenheit (58 degrees Centigrade). Lower temperatures than this produced internal tank temperatures approaching 160 degrees Fahrenheit (71 degrees Centigrade) in the Sahara Desert during the Second World War. The temperature of desert sand and rock averages 30 to 40 degrees more than that of the air. For instance, when air temperature is 110 degrees, the sand temperature may be 140 degrees.
Temperatures may get as high as 130 degrees Fahrenheit (54 degrees Centigrade) during the day and as low as 50 degrees during the night in arid areas. The drop in temperature at night occurs rapidly. A person who lacks warm clothing and is unable to move about, will chill quickly. The cool evenings and nights are the best times to work or travel. If you plan to rest at night, you may want to use a wool sweater, long underwear, and a wool stocking cap.
Temperatures during winter in USSR deserts and in the Gobi Desert can reach minus 50 degrees Fahrenheit (minus 45 degrees Centigrade). Low temperatures can be aggravated by very strong winds that produce high wind chill 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 can be as much as 72 degrees Fahrenheit. This imposes an unusual strain on personnel and sometimes affects equipment.
b. Winds and Sandstorms.
(1) Winds. Desert winds can achieve almost hurricane force. The effects of such force can be seen in Figure 1-5. Suspended dust and sand can make life almost intolerable, maintenance very difficult, and restrict visibility to a few meters. The Sahara Khamseen, for example, can last for days at a time. Although, it normally only occurs in the spring and summer. The "Seistan" desert wind in Iran and Afghanistan blows constantly from the north at 75 miles per hour for up to 120 days.
Figure 1-5. Wind Erosion Sahara.
(2) Sandstorms. Sandstorms (sand-laden winds) occur frequently in most deserts. Within Saudi Arabia, winds average 2 to 3 miles per hour (mph) and can reach 70 to 80 mph in early afternoon. You can expect major sandstorms and dust storms at least once a week. The greatest danger is getting lost in a swirling wall of sand. You should wear goggles and cover your mouth and nose with cloth. If natural shelter is unavailable, mark your direction of travel, lie down, and ride out the storm. Although no danger of a man being buried alive by a sandstorm exist, individuals can become separated from their units. In all deserts, rapid temperature changes follow strong winds. Dust and wind-blown sand interfere with radio transmissions.
c. Rain. The common characteristic of all deserts is their aridity. In areas of the Atacama in Chile, for example, no rainfall has been recorded for several years. When rain does occur, it may consist of one single violent storm in a year. Figure 1-6 shows high surface water run-off which, depending on soil consistency, will either reduce trafficability in loam of wadi areas or somewhat improve it if the terrain is pure sand. Precipitation may occur in the form of hail even though ground temperature is over 90 degrees Fahrenheit (32 degrees Centigrade).
Figure 1-6. Wadi After Rainstorm Sahara.
STAY OUT OF WADIS! |
When it rains, it's usually too much too quickly, and it is likely to be a liability rather than an asset. Some desert areas receive less than four inches of rain annually, and this comes in brief torrents that quickly run off the ground surface. Rain occurring as much as several hundred kilometers away can cause flooding in another distant location. Dry stream beds can suddenly become extremely hazardous as a channel of flooding. Therefore, reduce the time you spend in these low-lying areas. Do not set up camp in dry stream beds. Stories of walls of water 10 feet high roaring through them are true.
With the high desert air temperatures you cannot survive long without water. So in a desert survival situation, you must first consider "How much water do I have?" and "Where are other sources?"
d. Lightning. Lightning strikes frequently in the desert. Don't panic, keep exposure down to a minimum. Remember, track vehicles are grounded. You're better off inside than running around in the open.
5. Vegetation.
Vegetation is sparse in arid areas. You therefore will have difficulty finding shelter and camouflaging your movements. During daylight hours large areas of terrain are visible and easily controlled by a small opposing force. The indigenous vegetation and wildlife of a desert have adapted to the conditions. Some plants have extensive lateral root systems to take advantage of the occasional rain. Others have deep roots to reach subsurface water. For example, a palm tree indicates water within two to three feet (one meter) of the surface; salt grass implies that the water table is within six feet (two meters); cottonwood and willow trees indicate water at a depth of 10 to 12 feet (two to three meters). Other plants such as American cactus provide you no relation to the water table since they store moisture in enlarged stems. Some plants have drought-resistant seeds that lie dormant for years. Then, they have a brief colorful growth after a rainstorm. The available vegetation is usually inadequate to provide much shade, shelter, or concealment, especially from the air. Lack of natural concealment may induce temporary agoraphobia (fear of open spaces) in some soldiers new to desert conditions. This fear normally disappears after climatizing to the conditions.
6. Wildlife.
a. Invertebrates. Ground-dwelling spiders, scorpions, centipedes, and insects of most types, are found in quantity in the desert. Lice, mites, and flies, drawn to people for moisture or food, are not only extremely unpleasant, but they carry diseases such as scrub typhus and dysentery. The stings of many scorpions and the bites of centipedes or spiders can be extremely painful, though seldom fatal. However, some species of scorpion, black widow or recluse spiders can cause death.
b. Reptiles. Reptiles are the most characteristic group of desert animals. Lizards and snakes occur in quantity, and crocodiles are common in some desert rivers. Lizards normally are harmless. Although, exceptions occur in North America and Saudi Arabia. Also, you should avoid desert snakes since they can be extremely dangerous.
| WATCH WHERE YOU STEP. SNAKES ARE ESPECIALLY ACTIVE AT NIGHT DURING HOT WEATHER, AND YOU MAY SEE THEM COILED IN SHADY SPOTS DURING THE DAY. |
c. Mammals. The camel is the best known variety of specialized mammal life in the desert. Like most desert mammals, the urine of the camel is very concentrated to reduce water loss. A camel can lose 30 percent of its body weight without suffering distress. A proportionate loss would be fatal to man. The camel can regain this weight by drinking up to 27 gallons (120 liters) of water at a time. It cannot, however, continue indefinitely without water and can die of dehydration as easily as man in equivalent circumstances. Other mammals, such as gazelles, get all or most of their required water supply from the vegetation they eat and may live in areas where there is no open water. Smaller animals like rodents conserve their moisture by burrowing underground away from the direct heat of the sun, only emerging for foraging at night. These animals have adapted to the environment over thousands of years. Man has not done so and must carry his food and water with him.
CAUTION
BE CAREFUL WHERE YOU SLEEP IN THE DESERT!
d. Sleep Protection. The desert has few areas that offer protection, such as trees, from large vehicles. During short halts, sleep in or on your vehicle. When halting for more than an hour or more, designate a sleeping area that has a protective perimeter and always let someone know where you plan to sleep. When moving vehicles into an area where troops might be sleeping, use ground guides to look for sleeping troops. The ground is hotter than the air above so do not sleep directly on the ground, sleep on a cot. Snakes, spiders, and scorpions don't get to you so easily if you're on a cot.
7. Man-Made Characteristics.
a. Roads and Trails. Roads and trails are scarce in the open desert. There may be only simple commercial links. Some surfaces, such as lava beds or salt marsh, may prevent any form of routine vehicular movement. Ground transportation can often travel in any direction necessary. Speed of movement will vary depending on surface texture. Road systems that exist may 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. Many deserts have rudimentary trails for use by minor caravans and nomadic tribesmen. There may be wells or oases approximately every 20 to 40 miles (32 to 64 kilometers), although, there are some waterless stretches more than 100 miles (160 kilometers).
Trails vary in width from a few meters to more than 800 meters. In mountainous desert country, the enemy or climatic conditions can block available routes. Hairpin turns will be present on the edges of precipitous mountain gorges. Snow in winter may block the higher passes. The distances on foot or animal between two points in the mountains may be less than a tenth of the vehicular route.
b. Structures. Local inhabitants of deserts live in thick-walled structures with small windows, usually built of masonry or a mud and straw (adobe) mixture as shown in Figure 1-7. Nomadic tribesmen live in tents as shown in Figure 1-8. Conditions are such, that it will be difficult for you to find wood, since what is available is probably all ready in use.
Figure 1-7. Man-made desert structures.
Scattered across the deserts are the ruins of earlier civilizations. You may find ancient posts and forts in ruins. They usually command important avenues of approach and frequently dominate the only available passes in difficult terrain. Control of these positions may be crucial for any force intending to dominate the immediate area.
Figure 1-8. Desert Nomad Tents.
8. Resources.
a. Water. The lack of water is the most important single characteristic of the desert. Thus the population, if any, varies directly with the local water supply.
(1) Water Supply. Figure 1-9 shows a Sahara Oasis that, for its size, is one of the most densely occupied places on earth. There are permanent rivers such as the Nile, the Colorado, or the Kuiseb in the Namib Desert of Southwest Africa. Fed by heavy precipitation outside the desert, the river survives despite a high evaporation rate.
Ground water in such places as oases and near-surface wells is caused by subsurface seepage from considerable distances. The water you drink in a Sahara Oasis may have fallen as rain in the highlands of the south before the time of Christ.
Subsurface water may be so far below the surface, or so limited, that wells are normally inadequate to support any large number of people. Therefore, never take for granted any potable water supplies. You must maintain an adequate, uninterrupted supply. Thus, a large natural water supply may be both tactically and strategically important. Destruction of a water supply system may become a matter of political decision, rather than military, because of its lasting effects on the resident civilian population.
Figure 1-9. Typical Oasis - Egypt.
(2) Physical Need for Water. The subject of man and water in the desert has incited considerable interest and confusion since the early days of World War II when the U.S. Army was preparing to fight in North Africa. At one time the U.S. Army and the Israeli Defense Forces thought they could condition men to do with less water by progressively reducing their supplies during training. They called it water discipline. It caused hundreds of heat casualties.
| NOTE: | You can't drink too much water! |
A key to arid area survival is understanding the relationship between physical activity, air temperature, and water consumption. The body requires a certain amount of water for a certain level of activity at a certain temperature. A man performing hard work in the sun at 110 degrees Fahrenheit (43.3 degrees Centigrade) needs five gallons of water a day. Lack of the required amount of water causes a rapid decline in a person's ability to decide and to perform tasks efficiently.
Your body's normal temperature is 98.6 Fahrenheit (37 degrees Centigrade). Your body gets rid of excess heat by sweating. You sweat more as your body becomes warmer, whether caused by work, exercise, or air temperature. The more you sweat, the more moisture you lose. Sweating is the principal cause of water loss. A man will have a heat stroke if he stops sweating during periods of high air temperature and heavy work or exercise. This emergency requires immediate medical attention.
(3) Survival. Take measures to get the most from your water supply by understanding how air temperature and your physical activity affect your water requirements. These measures are:
- Find shade. Get out of the sun. Place something between you and the hot ground and limit your movements.
- Conserve your sweat. Wear your complete fatigue uniform including your T-shirt. Roll your sleeves down, cover your head, and protect your neck with a scarf or similar item to protect your body from hot blowing, sand-laden winds and the direct rays of the sun. Your clothing will absorb your sweat and keep it against your skin so you gain its full cooling effect. Your water requirement for survival drops dramatically by staying in the shade quietly, fully clothed, not talking, keeping your mouth closed and breathing through your nose.
- If water is scarce, do not eat. Food requires water for digestion. Therefore, eating food will use water that you need for cooling.
THIRST IS NOT A RELIABLE GUIDE FOR YOUR NEED FOR WATER. A person who uses thirst as a guide will drink only two-thirds of his daily requirement. To prevent this "voluntary" dehydration, use the following guide.
- At temperature below 100 degrees Fahrenheit (37.78 degrees Centigrade), drink one pint of water every hour.
- At temperatures above 100 degrees Fahrenheit (37.78 degrees Centigrade), drink one quart of water every hour.
Drinking water at regular intervals helps your body to remain cool, decreasing sweating. Even when your water supply is low, sipping water constantly will keep your body cooler and reduce water loss through sweating.
| NOTE: | You less water if you keep your clothes on! |
Conserve your sweat by reducing activity during the heat of day. DO NOT ration your water. If you try to ration water, you stand a good chance of becoming a heat casualty.
b. Minerals. In many desert areas, such as the Middle East, there is exploration for and exploitation of minerals, of which oil is the best known. Wells, pipelines, refineries, quarrying and crushing plants may be of strategic and tactical importance. Pipelines, often raised one meter off the ground, can inhibit your movements.
All arid regions have areas where the surface soil has a high mineral content (borax, salt, alkali, and lime). Material in contact with this soil wears out quickly. Water in these areas is extremely hard to find and undrinkable. Wetting your uniform in such water to cool off may cause a skin rash. The Great Salt Lake area in Utah is an example of this type of mineral-ladened water and soil. Avoid these types of areas, if possible. There is little or no plant life there and shelter is hard to find.
c. Agriculture. Many desert areas are fertile when irrigated, and some desert villages depend on irrigation canals, as shown in Figure 1-10. Agriculture in these areas has little affect on military operations except canals, which may limit surface mobility. The effect of the destruction of an irrigation system on the local population may become an important consideration in an operation estimate.
Figure 1-10. Irrigation Ditch - An Effective Tank Obstacle.
9. Navigation.
a. Navigation Effectiveness. A force may be equipped with modern, sophisticated navigation means with the ability to record positions with errors of less than one percent. A force not equipped with such systems may find navigation difficult, depending on the number of visible and known terrain features, and the reliability of local maps.
A specific person, qualified in celestial navigation and whose primary task is navigation, is often appointed by each company team and battalion task force.
Thoroughly brief soldiers on the type of terrain and the general environment they will encounter, including:
- Water sources, if any.
- Landmarks or significant permanent terrain features.
- Friendly and enemy areas of operation.
- Prevailing winds.
This information will assist navigation by reconnaissance units or individuals who become separated from their units.
b. Route Reconnaissance. To compensate for a lack of adequate maps, it is best to reconnoiter desert operations areas in advance of large-scale troop movements. Route reconnaissance is especially important in field artillery. Alternate and supplemental positions should be seen ahead of time. Go over and mark proposed and alternate routes. If possible, guides should return to the main element at the completion of the reconnaissance to help the unit stick to the prescribed routes of march. Deviation from planned routes can cause lengthy delays and breakdowns that will ultimately degrade available fire support. Thorough ground reconnaissance and adherence to prescribed routes of march will improve artillery fire support in desert operations.
c. Routes of March. There are few hard surface roads within the interior of Saudi Arabia, for example, but many of them are ill maintained. Secondary gravel roads and trails crisscross the landscape, but they are also ill maintained and frequently are like driving on a "washboard." Except for the main arteries, there are few road signs or trail markers except those constructed by the bedouins. Routes of march will quite often be cross-country over rugged and hanging terrain with only partially adequate maps and a compass.
d. Evasion. As an evadee, you should follow the principles of desert camouflage:
- Hide or seek shelter in dry washes (wadis) with thicker growths of vegetation and cover from oblique observation.
- Use the shadows cast from brush, rocks, or outcroppings. The temperature in shaded areas will be 20 to 30 degrees cooler than the air temperature.
- Cover objects that will reflect the light from the sun.
Before moving, survey the area for sites that provide cover and concealment. You will have a problem estimating distance. The emptiness of a desert terrain causes most people to underestimate distance by three: what looks like one mile (1.61 kilometers) away is really three miles (4.83 kilometers) away.
e. Lost or Stranded. People die every year in the desert because they don't know what to do if lost or stranded. It is a good idea to have at least two vehicles in your traveling party. Use the buddy system. When driving, avoid going down steep slopes your vehicle may not be able to climb back up. Look for washouts, large rocks, and deep sand. If you get stuck, try jacking the vehicle up and then placing boards, brush, or blankets under the tires. Always let someone, friends or superiors, know
- where you are going.
- when you plan to return.
- when to start searching if you don't return.
Note: Don't forget to check in when you return.
If lost, don't panic. Remember the sun rises in the east and sets in the west. When leaving your field site, know the direction in which you are departing. If needed, make a field expedient compass:
- Put a stick in the ground, and lay a rock at the end of the shadow from the stick.
- Wait 15 minutes.
- Draw a line from the rock to the new end of the shadow. The line represents the east-west line.
- In the morning, the rock will be the west end; in the afternoon, the rock will be the east end.
If your vehicle breaks down, stay near it. Your emergency supplies are there. Your vehicle has many items that are useful in an emergency. Raise the hood to show you need help. A vehicle can be seen for miles, but a person on foot is very difficult to find. Tie a white or light-colored cloth to your antenna. Use mirrors and burn oil for signaling. When not moving, use available shade. You can make shade by erecting tarps, blankets, seat covers or anything to reduce the direct rays of the sun.
| DO NOT SIT OR LIE DIRECTLY ON THE GROUND; IT CAN BE HOTTER THAN THE AIR BY 30 DEGREES OR MORE. IF YOU HAVE WATER, DRINK IT. DO NOT RATION IT. |
If water is limited, keep your mouth shut. DO NOT talk, eat, smoke, drink alcoholic beverages, or take salt.
| KEEP YOUR CLOTHING ON; IT HELPS KEEP THE BODY TEMPERATURE DOWN AND REDUCES THE DEHYDRATION RATE. COVER YOUR HEAD. IF A HAT OR CAP ISN'T HANDY, IMPROVISE. |
PART B - PREVENTION, IDENTIFICATION AND TREATMENT
OF HOT AND COLD WEATHER INJURIES IN THE DESERT
No matter how much instruction people receive on how to avoid becoming overheated, some heat casualties will occur.
1. Heat Casualties.
Your body regulates its temperature within very narrow limits. Too little salt may lead to heat cramps and too little salt and not enough water may lead to heat exhaustion. A general collapse of the body cooling mechanism will lead to potentially fatal heat stroke. To avoid these illnesses, you must be physically fit, thoroughly acclimatized, and drink sufficient water with necessary salt. If you expend more calories than you take in, you will be more prone to heat illnesses. Your people may lose their desire for food in hot climates, so you must encourage them to eat. Schedule the heavier meal of the day for the cooler hours.
Continued supervision by commanders and the use of the buddy system are important, especially for those personnel, such as mechanics, who work alone or in pairs. You must recognize heat stress symptoms quickly. When a person is suffering from heat stroke, they will have a tendency to creep away from their comrades and try to hide in a shady and secluded spot. If not found and treated, they will die. You can prevent heat stroke by providing shade during the day. Use tarpaulins or camouflage nets, preferably doubled to allow air circulation between layers. Dampened them with any surplus water.
The following are the major types of heat casualties and their treatment when little water and no medical assistance are available:
a. Heat Cramps. Heat cramps are caused mainly by loss of salt due to excessive sweating. Symptoms of heat cramps are moderate to severe muscle cramps in legs, arms, back or abdomen and a normal body temperature. These symptoms may start as mild muscular discomfort. When this occurs, you should stop all activity, get in a cool shaded place, and drink water. Promptly relieve heat cramps by replacing the salt lost from the body. If you fail to recognize early symptoms and continue with physical activity, you will have severe muscle cramps and pain. To treat a patient with heat cramps, take the following steps immediately:
- Get the patient under shade. Make him lie on a stretcher or similar item approximately 18 inches off the ground.
- Loosen the patients clothing.
- Elevate the patient's feet and either move legs up and down or massage them.
- Sprinkle the patient with water, and fan him.
- Give the patient all the water he can drink in small amounts in the form of 0.1 percent saline solution.
- Ensure the patient remains quiet and rests.
- Refer the patient to a medical officer.
b. Heat Exhaustion. Heat exhaustion results from a large loss of body water and salt. Symptoms are headache, mental confusion, irritability, excessive sweating, weakness, rapid pulse and breathing, dizziness, vomiting, cramps, and pale, moist, cold (clammy) skin. There may be a slight rise in temperature. Treat a patient for heat exhaustion using the same immediate steps as listed above for heat cramps:
c. Heat Stroke. Heat stroke is a severe heat injury caused by extreme loss of water (collapse of body cooling mechanism) and salt and the body's inability to cool itself. Temperature is high (106 or more). The patient may die if not immediately cooled. Symptoms are no sweating, hot, dry skin, headache, weakness, dizziness, rapid breathing, fast pulse, nausea and vomiting, and mental confusion and bizarre behavior leading to unconsciousness. Heat stroke is a medical emergency, seek the aid of a medical officer at once. The lowering of the patient's body temperature as rapidly as possible is the most important objective. To treat a patient with heat stroke, take the following steps immediately:
- Get the patient in shade. Lay him on a stretcher or similar item approximately 18 inches off the ground.
- Loosen the patient's clothing.
- Sprinkle water on the patient or bathe him (it does not matter if the water is polluted or brackish), fan him to increase the cooling effect.
- Massage the patients's arms, legs, and body.
- If the patient regains consciousness, let him drink small amounts of water every three minutes.
- For medical evacuation, continue treatment on the way.
2. Heat Illness Prevention.
An individual who has had a heat stroke or a severe case of heat exhaustion is more likely to fall sick again than one who has not suffered from these illnesses. Hence, individuals once affected should be subsequently exposed to heat stress with caution.
The following symptoms can distinguish between salt depletion and water depletion.
| Symptoms | Salt Depletion | Water Depletion |
| Duration of symptoms | 3 to 5 days | 1 day |
| Thirst | seldom | prominent |
| Fatigue | prominent | seldom |
| Cramps | prominent | none |
| Vomiting | prominent | none |
| Weakness | progressive | acute |
a. Water Requirements Guide. This guide is based on 80 degrees Wet Bulb Globe Temperature (WBGT) which equals approximately 105 degrees Fahrenheit (40.5 degrees Centigrade) dry bulb temperature in a hot dry desert. The dry bulb temperature inside a tank may be significantly higher than the outside temperature. Vehicles of some countries have inside insulation, and some vehicles have air conditioning. You will need extra water for cooking, vehicle radiators, etc.
Quarts per man per day for drinking. |
|||
| Activity | Typical Duties | Under 80 degrees | Over 80 degrees |
| Light | Deskwork. Guard duty Radio operating. | 6 | 10 |
| Moderate | Route march on level ground. Tank operations. | 7 | 11 |
| Heavy | Forced marches. Route
marches with heavy loads or CBR clothing. Digging in. |
9 | 13 |
b. Salt Requirements Guide. Described below are two methods of making up a solution of 0.1 percent salt in drinking water. Use table salt throughout, and vigorously stir or shake the container after adding the salt. To prepare the solution (approx. 26 percent), dissolve 9 level table spoons of salt in 2/3 canteen cup water. Follow logical progression; that is, 3 spoonfuls to 3 gallons, 12 spoonfuls to 12 gallons, etc.
| NOTE: | Check your current SOP for doctrine that may advise against taking salt tablets under certain conditions. |
(1) Addition of Table Salt to Water
| Table Salt | Amount of Water |
| 2 ten-grain crushed salt tablets or 1/4 teaspoon | 1-quart canteen |
| 4 ten-grain crushed salt tablets | 2-quart canteen |
| 1 1/3 level mess kit spoons | 5-gallon can |
| 9 level mess kit spoons or 3/10 pound | 36-gallon-lister bag |
| 1 pound | 100-gallon tank |
| 1 level canteen cup | 250 gallons (in water trailer) |
(2) Addition of Saturated Salt Solution
| Amount of Solution | Amount of Water |
| 1/2 canteen cup (quart size) | 1-quart canteen |
| 1 canteen cup (2-quart size) | 2-quart canteen |
| 1 mess kit spoonful | 1 gallon |
| 2/3 canteen cup | 36-gallon lister bag |
| 4 canteen cups | 250 gallons (in water trailer) |
c. Acclimatization. The following schedule shows work that may be performed during a period to acclimatize soldiers in the minimum time. Full acclimatization is attained most efficiently by graded, progressively increasing work in the heat over a period of approximately 14 days. Rest days will be of limited value. Modified the schedule consistent with local conditions.
d. Jet Lag. People arriving in Saudi Arabia from the United States need at least two or three days' after flight recovery time. Jet lag affects eating and sleeping habits, mental agility, and general attitude. A newcomer cannot "hit the ground running."
Jet lag is a serious consideration in desert operations undertaken by men arriving by plane from a great distance. Allow for a recovery period, ideally one day for every time zone crossed.
3. Precautions.
In a desert survival/evasion situation, it is unlikely that you will have a medic or medical supplies with you to treat heat injuries, so take extra care to avoid heat injuries. Rest during the day and do your work during the cool evenings. Use a buddy system to watch for heat injuries, and follow these guidelines:
- Make sure you tell your buddy where you are going and when you will return.
- Watch your buddy for signs of heat injury. If he complains of being tired or wanders away from the group, he may be a heat casualty.
- Make sure your buddy drinks water at least once an hour.
- Get in the shade when resting. Do not let your buddy lie directly on the ground.
- Do not let your buddy take off his shirt and work during the day.
- Check the color of your urine. A light color means you are drinking enough water and, a dark color means you need to drink more.
Figure 1-11 shows how you can determine a man's water needs at three activity levels in relation to the daily mean air temperature.
Figure 1-11. Daily Water Requirements for Three Levels of Activity.
4. Arid Area Hazards.
There are several hazards unique to desert survival. These include insects, snakes and other reptiles, thorny plants and cacti, contaminated water, sunburn, eye irritation, climatic stress, and poor personal habits.
a. Insects. Insects of most types abound in the desert. Lice, mites, wasps, and flies, which are drawn to man as a source of moisture and food, are extremely unpleasant and may carry diseases such as scrub typhus and dysentery. Some species of spiders and scorpions can cause death. Old buildings, ruins, and caves are favorite habitats of spiders, scorpions, centipedes, lice and mites. These areas provide protection from the elements and attract other wildlife. Therefore, take extra care when staying in these areas. Always wear gloves in the desert. Do not place your hands anywhere without first looking to see what is there. Visually inspect an area before sitting or lying down. When you get up, shake out and inspect your boots and clothing.
b. Snakes and Reptiles. Snakes and reptiles are found in all arid areas and snakes are probably the most common threat. They inhabit ruins, native villages, garbage dumps, caves, and natural rock outcroppings that offer shade. Never go without boots or walk through these areas without carefully inspecting them for snakes. Watch where you place your feet and hands. Most snakebites result from stepping on or handling snakes. Avoid them. Once you spot them, give them wide berth. Consider all snakes dangerous. Even a bite from a harmless snake can become infected. Take no chances and treat all snake bites as poisonous. Use the following steps for FIRST AID FOR SNAKE BITE:
(1) Remain calm, but act swiftly. Call MEDEVAC Immediately.
(2) Within practical limits, keep the bitten part very still, below the level of your heart and as cool as possible.
(3) Tie a slightly tight band or tourniquet 2 to 4 inches toward the heart from where the bite is. You can use a belt, rag or sock and a stick. Keep moving the band ahead of the swelling if it moves closer to the rest of your body. Tie the band tight enough to halt blood flow in surface blood vessels, but not tight enough to stop the pulse.
(4) If you estimate that you cannot get to medical attention within 15 to 20 minutes, make a cut over each fang mark no more than a half-inch long and one-fourth inch wide. Make the cuts along the length of the bitten limb (parallel).
(5) Apply suction to the wound. If a snakebite kit is available, use its suction pump. If none is available, apply suction by mouth, spitting out the blood and other fluids frequently. The venom is not harmful in the mouth, unless there are cuts or sores. Even so, risk is not great. Maintain suction at least 15 minutes before loosening the tourniquet.
(6) All snakebite victims should be taken to the hospital.
(7) If bite is poisonous, and if MEDEVAC is not available, continue the process in para (5) above.
c. Contaminated Water. You should always assume that water found in arid areas is contaminated and treat it properly. Drinking untreated water will result in skin diseases and dysentery, causing excessive water loss. Do not use untested water for washing clothes. Although you can use it for vehicle cooling systems or vehicle decontamination.
d. Sunburn. Sunburn results from overexposing your skin to the sun's rays. So keep your body completely clothed, including gloves on your hands and a scarf around your neck. Use sunburn cream liberally on any exposed areas of skin. Sun poisoning equals nausea and dehydration. In addition, burns may become infected, causing more problems.
| Note: | Unless otherwise ordered, keep your sleeves rolled down to guard against sunburn. |
Remember that:
- There is as much danger of sunburn on cloudy days as on sunny days, especially at high altitudes.
- Sunburn ointment does not give complete protection against excessive exposure.
- Sunbathing or dozing in the desert sun can be fatal.
e. Human Waste Disposal. Proper disposal of human waste is essential. Bury feces and cover urine to prevent attracting flies. If possible, wash hands after defecating or urinating and before each meal. Clean eating and cooking utensils. You must follow good sanitation procedures to lessen the danger of gastrointestinal disorders, which lead to excessive moisture loss.
f. Diseases. Diseases found in the desert include plague, typhus, malaria, dengue fever, dysentery, cholera, and typhoid. Vaccines or prophylactic measures can prevent some of these diseases. Also, high levels of field hygiene and sanitation can prevent disease where there are no vaccines or prophylactic measures.
Vaccines can prevent typhoid and cholera. Fleas and lice carried by rats and other animals, transmit typhus and plague. Proper sanitation and personal cleanliness can help prevent these two diseases. Drinking impure water and eating contaminated foods cause dysentery. Water used for drinking, cooking and bathing must be tested before use. Drink bottled water if available.
g. Fungus Infections and Prickly Heat. The excessive sweating common in hot climates can aggravate 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 diseases are likely in humid conditions.
h. Respiratory Diseases and Cold Weather Injuries. Soldiers 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.
Dust particles that trigger sinus problems and other respiratory ailments, fill the air, even on clear day. It is not practical or feasible to attempt to filter out the dust particles on a daily basis; however, on particularly bad days, personnel do don surgical masks or cover their nose and mouth with a bandanna to reduce the intake.
| EXPECT A HIGHER-THAN NORMAL INCIDENCE OF RESPIRATORY DISORDERS. |
i. Infections from Polluted Water. Polluted water causes skin diseases, so don't use untested water for washing clothes. However, you can use untested water for vehicle cooling systems or vehicle decontamination.
j. Climatic Stress. The glare on the sand causes eyestrain, and wind-blown, fine sand particles can irritate the eyes and cause inflammation. Wear goggles and use eye ointments to protect your eyes. The combination of wind and sand or dust can cause your lips and other exposed skin to chap. Use chapstick and skin ointments to prevent or overcome this problem. The sudden and extreme temperature shifts in arid areas can cause chest colds. Wear warm clothes at night to prevent chills. Desert environments can cause stress to the body and mind. Some stress-rendering factors are:
- Extreme heat during the day with sudden temperature drops in the evening.
- Constantly blowing, sand-laden winds.
- Extensive barren areas, which bring on depression.
Rest is vital in this environment: You need 20 minutes of rest for each hour in the heat and six hours of sleep each day.
1. Intensity of Light.
Intense sunlight and heat are present in all arid areas. Air temperature can rise as high as 140 degrees Fahrenheit (60 degrees Centigrade) during the day. As illustrated in Figure 1-12, heat gain results from:
- direct sunlight.
- hot blowing winds.
- reflective heat (the sun's rays bouncing off the sand).
- conductive heat from direct contact with the desert sand and rock.
Figure 1-12. Types of heat gain.
Intense sunlight and heat increase the body's need for water. To conserve your body sweat and energy, you need a shelter to reduce your exposure to the heat of the day. Travel at night to minimize the use of water. You can survey the area at dawn, dusk, or by moonlight when there is little likelihood of mirage. Radios and sensitive items of equipment exposed to direct intense sunlight will malfunction.
2. Radiant light.
As seen in Figure 1-13, the sun's rays either direct or bounced off the ground, can affect your skin. Overexposure will cause sunburn. Persons with fair, freckled skin can experience eyestrain and temporarily impaired vision. Skin, such as ruddy complexions, and red hair are more susceptible to sunburn than others. Everyone is susceptible to some degree. Sunburn produces painful reddened skin that can result in blistering and lead to other forms of heat illness.
Figure 1-13. Radiant Light From All Directions and Protecting the Back of Your Neck
- 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.
- Excessive sunbathing or dozing in the desert sun can be fatal.
Radiant light or its heat effects may be detrimental to plastics, lubricants, pressurized gases, some chemicals, and infrared tracking and guidance systems. You must keep items such as C02 fire extinguishers, M13 decontamination and reimpregnating kits, and Redeye missiles out of constant direct sunlight. Certain optics have discolored under direct sunlight (although this is unusual), so it is wise to minimize their exposure to the sun.
3. Visibility.
As a general rule, a force attacking in daylight should try to have the sun comparatively low and behind it. The assaulting force can see enemy targets plainly without their shadows, while glare, mirages, and haze handicap the defenders. It is not always possible for the sun to be directly behind the attackers and it is not essential. To rely on this leads to a stereotyped method of attack, which would become known to the defenders. As shown in Figure 1-14, the commander of a maneuver force should attempt to keep the sun somewhere on a 3,200-mil arc to his flanks or rear, giving a wide choice of angle of attack.
Figure 1-14. Attack from the Sun.
A powerful sun and low cloud density combine to produce unusually bright and glaring light conditions during the day. In certain circumstances, light allows such unlimited visibility that gross underestimation of distance is common. Visibility may be degraded by mirages or heat shimmer caused by heated air rising from the extremely hot desert surface. This happens when the observer is looking into the sun or through magnifying optical instruments. (Note the effects of the mirage in Figure 1-17.)
Because mirages distort the shape of objects, particularly in the vertical dimension, observation is best at dawn and dusk when the air is cooler. Positions selected for observation posts should be as high above the desert floor as possible. Vision with night observation devices and even with the naked eye is exceptionally good on moonlit nights.
| NOTE: | A good way to measure distance is to use your vehicle odometer. |
4. Levels of light.
Light levels in desert areas are more intense than in other geographic areas. Moonlit nights are usually crystal clear; winds die down, haze and glare disappear, and visibility is good. You can see lights, red flashlights, and blackout lights great distances away. Noise carries far. Conversely, during nights with little moonlight, visibility is extremely poor. Travelling is extremely hazardous; you must take care to avoid
- getting lost.
- falling into ravines.
- stumbling into enemy positions.
Movement during such a night is practical only if you have a compass and have spent the day in shelter, resting, observing and memorizing the terrain, and selecting your route.
5. Darkness.
Many offensive operations take place at night. Observation in these conditions varies according to the amount of ambient light. A near full moon and the clear desert sky allow for good observation, both with the naked eye and with night observation devices. Maneuvering units using night vision devices must continually scan the surrounding terrain to pick up enemy activity that would be acquired by peripheral vision in daylight.
When there is no moon or very little moon, the desert night is extremely dark. Under these conditions, passive vision devices (except for thermal imagery) are of little value. You will have to rely on active light sources. However, to maintain surprise in an operation, headquarters must strictly control the employment of artificial light. As a general rule, direct-fire weapons with muzzle-blast debris-kickup should not illuminate their target themselves. Following contact, when some targets should be on fire, you can use passive devices.
6. Prepositioned lights.
This method places two or more searchlights far apart, as shown in Figure 1-15. They are behind the line of contact, beyond enemy artillery range, and concealed from enemy ground observation. Area units determine their locations by resection, using the vertical beams of the lights. Enemy air threats may require the lights to be well away from friendly units. Move the lights on a time schedule known to each unit.
Figure 1-15. Using Resection on the Vertical Beams of Prepositioned Lights.
7. Light and noise.
Light and noise at night may be seen or heard from miles away, so strict light and noise discipline is necessary. Enemy passive night vision devices can pick up light sources of any color at greater ranges than the unaided eye. One momentary lapse may be enough to attract enemy attention and permit enemy resection. Muffle and keep to the minimum essential noise such as those produced by generator motors. Units should start all engines together. This will confuse the enemy as to the number and direction of the vehicles. Do not use lights inside any vehicle unless there is no possibility of leakage. Equipped command vehicles come with automatic door switches and blackout vestibules. If you must use external lights for any purpose, they should be dark blue or dark green and capable of being dimmed by rheostats. Permanently cover items such as brake lights. Figure 1-16 illustrates this problem.
Figure 1-16. Camouflage Light and Noise at Night.
8. Noise.
Psychological Operations units may use noise to create a false impression of strength or movement, or to lure an enemy force into an area where fires can be concentrated against them. Noise, particularly effective at night, carries far, but it is affected by wind strength and direction. Noise may be recorded. A line of powerful tape recorders can easily simulate a column of tanks or helicopters on the move. However, you can produce a situation different than that intended. It is essential that the amplifier hum is not heard. Deliberate natural noise, for example, the clang of dropped cans or a closing tank hatch, can easily be overdone by constant repetition.
9. Dust.
The normal dust column raised by movement can be used to an advantage. You can make a fake helicopter landing zone more realistic with decoy aircraft and a jeep towing chains between the "aircraft," giving the impression of aircraft hovering close to the ground. A few real aircraft flying Nap of the Earth (NOE) can give the impression of a great deal of activity.
Dust is an observation hazard to a maneuvering force, especially in situations of little or no wind. Teams should move in levels with "bounding" overwatching elements on the upwind side. Observers and attack helicopters must operate well to the flank. Since it is impossible to disguise daylight movement, the assault should be as rapid as possible to minimize enemy reaction time.
10. Range observation at great distances.
A person standing on a hill 300 meters high can see, depending on the landscape, for 20 or 30 km on a clear day. Land that looks flat from the hill actually has two ridgelines in that distance. The uniform color of the land and the even lighting at midday make it difficult to distinguish changes in elevation at great distances. The effect is similar at near range. Soldiers frequently aim at an enemy vehicle with a recoilless rifle without noticing the stretch of low ground in between. The round falls short. It is not a question of carelessness, but of an optical illusion that affects range estimation and targeting.
The casual observer will frequently miss intermediate features in the landscape. An observer must think about what he sees, and look for the unexpected. (Such problems in observation decrease at dawn and dusk, when shadows define terrain features.)
Mirages and Haze. Figure 1-17 shows an optical phenomena caused by the refraction of light through heated air rising from a sandy or stony surface. They occur in the interior of the desert about six miles (9.6 kilometers) from the coast. They make objects that are one mile (1.6 kilometers) or more away appear to move. This mirage effect makes it difficult for you to identify an object from a distance. It also blurs distant range contours so much that you feel as if you are surrounded by a sheet of water from which elevations stand out as "islands." The mirage effect makes it hard for a person to identify targets, estimate range, and spot personnel. However, if you can get to high ground (ten feet or more above the desert floor), you can get above the super-heated air close to the ground and overcome the mirage effect. Mirages make land navigation difficult because they obscure natural features.
Figure 1-17. Close-up (left) and Effects of Mirage (right).
In some circumstances camouflaged equipment or positions less than a meter from the ground are invisible to about 2,000 meters. Moreover, mirages allow observation of objects below the horizon. Although these effects may be distorted, enlarged, or fuzzy and unrecognizable, they depend entirely on the angle of the sun to the observer and are best combated by:
- Maintaining observers as high above the desert floor as possible, even if only in tanks hull-down behind the tops of sand dunes.
- Observation over a wide area by vehicle crews. This may allow a vehicle on one side of a position to warn one on the other side of a possible threat to his front.
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