 When most people discuss a cold land environment, they usually think of the classic arctic environment even though a cold land environment can exist over any region you fly. A cold land environment exists when the temperature is cold enough to cause harm to the body. Hypothermia is the greatest threat in a cold land environment. It most commonly occurs in temperatures that are just under 50 degrees Fahrenheit. A little sweat, a little wind plus inadequate clothing can add up to trouble. A big problem in flying over cold land environments is that most crews dress for comfort in the cockpit and not for the outside environment. If the aircraft goes down, the result is an unprepared crew in a hostile environment. The human body is best suited for tropical or semi-tropical areas. Maintaining proper body temperature in a cold land environment will be your top priority. An unprotected human being cannot withstand extreme temperature changes. As the ambient temperature drops, the body core temperature also drops. This is known as hypothermia. To understand how hypothermia manifests itself, we must first understand how the body maintains its normal core temperature. Through the process of metabolism, the body core maintains an average temperature of 98.6 degrees Fahrenheit. As long as heat loss does not exceed heat buildup, the body will function normally. However, if heat is lost from the body too quickly, it will lower body core temperature. As the body core temperature drops, so does mental and physical efficiency. Heat is lost from the body through four different mechanisms. Radiation, conduction, convection, evaporation. Radiation is the transfer of heat waves from the body to the environment or from the environment back to the body. Radiation is considered the primary cause of heat loss. An example of radiation would be to expose a person to a cold environment without adequate protection. Since up to 50% of body heat loss occurs through the head and neck, exposing these areas could cause a rapid loss of body core temperature. This is why it is imperative to keep the head and neck areas covered while in a cold land environment. Conduction is simply the movement of heat from one object to another. One reason why survival experts suggest that survivors evacuate the fuselage when temperatures are below 10 degrees Fahrenheit is that the cold metal will draw the body temperature down through conduction. It is even more dangerous to handle liquid fuel at low temperatures. Unlike water, the liquid fuel will not freeze at 32 degrees Fahrenheit, so whatever temperature it is exposed to will be the temperature of the fuel. If the temperature is well below zero, coming into contact with the fuel can cause instant frostbite. Convection is described as heat movement by means of air or wind to or from an object or body. Through radiation and conduction, the human body is always warming a thin layer of air next to the skin. The temperature of this layer is nearly the same as that of the skin. If this layer stays next to the body, it provides an insulative layer that helps to keep the body warm. However, when this layer of air is removed by convection, the body temperature will lower. Wearing proper clothing can help protect this insulative layer from convection. Evaporation is a process through which liquid is converted to a gas, and during this process, heat within the liquid escapes to the environment. The body uses this method to regulate core temperature when it perspires and air circulates around the body. If water vapor cannot evaporate through clothing, it will condense, freeze, and reduce the insulation value of the clothing. It will also cause the body temperature to go down. For this reason, it is suggested you wear fabrics that breathe. Once body core temperature starts to drop, the body will begin to defend itself. Capillaries and smaller vessels near the surface of the skin will constrict to keep blood from coming in contact with the cooler skin. This gives the skin a bluish or ashy color. Shivering will usually be the next symptom. This is the body's attempt to produce heat through muscular contraction. At first, the shivering usually is mild. Then it progresses to a more violent form. As muscles begin to cool and stiffen, muscular coordination is lost. Speech will become slurred as mental faculties and judgment begin to slow. As the blood cools and thickens, the pulse will become weak and irregular. Unconsciousness may be only minutes away due to hypoxia. Another important fact concerning hypothermia is that fatigue will accelerate its onset. Hypothermia is just one medical consideration in a cold land environment. Others include snow blindness, frost nip, and frost bite. Snow blindness is a condition where the outer layer of the eyes have been sunburned. In snow-laden areas, sunlight reflected off the snow is the main cause. The primary symptoms are redness and burning of the eyes. Headache, poor vision, pain, and swelling may also accompany the primary symptoms. Prevention is the best medicine. When out on sunny days, wear some type of protective eyewear. If your survival kits have sunglasses, use them. Even prescription glasses will afford some protection. Treatment for snow blindness includes covering both eyes for 18 hours and applying a cold compress to relieve pain and swelling. Frost nip is the freezing of the superficial layers of skin. It is caused as a result of skin exposed to cold and windy conditions. Symptoms include whitening of the affected area. The affected area will also feel waxy to the touch. Fingertips, earlobes, nose, cheeks, and chin are the areas most vulnerable. To prevent frost nip from happening, adequate clothing is a must. When outside of a shelter, keep all body areas covered. Treatment is very simple. Warm the affected area with body heat and protect the affected area from further freezing. Frostbite is the freezing of tissues, which may include the skin, muscles, tendons, and bone. When the cells in tissue freeze, all cellular activity ceases. Ice crystals may form and draw water from the cell. Ice crystals can cause physical damage to the cells. Also, the cells can no longer take up oxygen and eliminate waste products. Some symptoms of frostbite include a waxy skin color and skin texture that is resilient to the touch. There is also a deep numbness to the affected area. The hands and feet are the areas most affected. A very important fact to remember is that once a limb becomes frostbitten, it is more likely to suffer frostbite during subsequent exposures. To prevent this condition, always try to keep the feet warm and dry. When handling cold items or snow, wear gloves. If you do fall victim to frostbite, treatment in the field will be extremely limited. The best advice is to cover and protect the body from further freezing until medical help can be sought. Do not rub with snow. This will promote a deeper frostbite. Do not soak in kerosene. This is just an old wives' tale and will not help. Do not try to thaw the area in hot water. This is a very painful process and could cause further complications. Dehydration Dehydration in a cold environment may sound a little strange, but if care is not taken, a person could slip into dehydration very quickly. The thirst mechanism will be weakened and could reach the point where it is totally ignored. Remember, just because you are experiencing a cold environment does not mean your water requirements have changed. For a more in-depth discussion on dehydration, refer to our Hotland Survival Training Module. Finding water will be easy enough, but remember, you should not consume water unless it has been purified. Boiling water for five minutes or longer if at higher altitudes or utilizing water purification tablets will be the easiest methods. Never eat snow. The snow crystals can cause damage to the mouth and tongue and will also lower body core temperature. Place the snow in a leak-proof container and set it next to the fire to melt. Another method to melt snow is to place the container between layers of clothing. The first line of defense against the threats of a cold land environment is shelter. Shelter can be broken down into two separate categories, immediate and long-term. Immediate shelter is considered your first line of protection from the environment. Clothing will be your most immediate shelter against any environment. The clothes you are flying in and the extra clothes you bring on a flight for a cold land emergency might be different. Use the following recommendations when on the ground in a cold land survival environment. Your clothing will provide you with an immediate means to retain body heat. The type of clothing you choose can help or hinder your attempt to insulate. The insulative quality of any material is dependent on the amount of trapped air in the material. An important fact to keep in mind is that when most clothing becomes wet, it loses its insulative quality. Wet clothing in the wind will draw off body heat 20 times faster than wind alone. It is also important to keep your clothing clean. As dirt fills in between the fibers of a fabric, it also fills in the dead airspace that gives clothing its insulative quality. A checklist that survivors can utilize to ensure insulative effectiveness is known as the colder principle. C. Keep clothing clean. O. Avoid overheating. L. Wear clothing loose and in layers. D. Keep clothing dry. E. Evaluate the need for additional clothing. R. Keep clothing in good repair. One of the best natural insulative materials is wool. Wool will insulate even when it becomes wet. A general rule for dressing in a cold land is to wear a layer of cotton next to the skin to absorb and retain moisture, followed by a layer of wool with a water-resistant material on top. When dressing for a cold land environment, dress in layers. Wear proper clothing to keep you warm during the coldest times of the day when there may be little activity. If the outside temperature rises or the body temperature rises due to a high level of activity, the survivor can peel off layers of clothing as needed to regulate the heat loss. It is a good idea to get in the habit of dressing with four layers of clothing. Layer 1. The first layer consists of undergarments such as underwear and socks. Layer 2. The second layer consists of shirts, pants, boots, hats, and glove liners. Wool is the preferred fabric for the pants. Cotton and denim should be avoided due to their poor insulative quality when wet. Boots should be fitted properly. In colder regions, boots should be fitted to allow for a pair of polypropylene socks, plus one or two pairs of heavy wool socks. Hats should have the capability of covering the ears as well as the head. The best materials for hats are wool, polypropylene, or acrylic. Polypropylene is also a good material for glove liners. Layer 3. The third layer consists of a parka, windpants, or warm-up pants, and mittens or gloves. The parka jacket should be made of windproof and water-resistant material. It should also have a hood with a drawstring to minimize the opening to the face. A Dacron or Gore-Tex shell and down or Thinsulate insulation are materials that will work well for the parka. Mittens will tend to keep your hands warmer than gloves, but you will lose dexterity of the fingers. Fourth layer. The fourth layer can consist of quilted pants or over boots. By wearing proper clothing, you have taken the first step in providing shelter for yourself. However, this does not mean you should rely solely on your clothing for shelter. A shelter from the elements needs to be constructed as soon as time and conditions permit. Materials to construct a shelter may be scarce. It is important to keep in mind that if the temperature is below 10 degrees Fahrenheit, shelter other than the aircraft should be sought. This is because the metal in the fuselage will act as a cold sink and draw heat from the body. Natural formations can also shield survivors from the elements. These natural shelters can consist of overhanging ledges, fallen logs, or caves. Another readily available shelter is the life raft. If available, it should be inflated to provide protection from the elements. The raft provides the survivor with an alternative source of shelter, which gives immediate protection from the wind. Other forms of immediate shelter can include an emergency poncho, garbage bags, or a solar blanket. No matter what type of shelter is used, here are a few basic guidelines to remember. Location Stay near the aircraft. Air rescue parties will be looking for the aircraft and any debris. Look for any possible hazards when selecting a site for shelter. Dead trees could lose their tops or limbs and come crashing down on the shelter. Look for the possibility of an avalanche or rock slide area. Because of the risk of flash floods, stay out of dry stream beds. If possible, place the shelter under a tree line to give added overhead protection from the elements. Material Many aircraft parts can be used for a shelter. The aircraft's interior has many more resources than the exterior. Fabric on the seats, floors, and walls can be readily used. Natural foliage, such as leaves, grass, and tree boughs, are there for the taking. Snow can also be used as material to build a shelter. Although it is very cold, it makes excellent insulation for existing shelters. Fuel source Stay near the resources needed to maintain a fire. If there is too much distance between the shelter site and the resources, much needed energy will be expended just to maintain a fire. Water source Being close to a water source is one primary consideration. Although it is wise to stay close to a water source, do not construct the shelter too close to these areas, as they are typically cooler and damper. Signaling If possible, select a site that will allow a signal to be seen from all directions. As a general rule, if the site obscures your vision, rescuers won't see you. Remember, the most promising signal is the aircraft wreckage. Keep it visible and stay near it. The effectiveness of any shelter lies in its insulation. As previously mentioned, the best insulation, if available, is snow. But if you have covered the shelter with snow, it is no longer an effective signal. Immediate needs for shelter insulation may outweigh visibility considerations. These factors need to be judged on a case-by-case basis. Once inside the shelter, body heat will begin to warm the shelter. Scraping down to bare earth will increase the inside temperature by about 12 degrees, even if it is sub-zero outside. By lighting a candle, it is possible to raise the temperature by another 4 degrees. Keep the shelter just big enough to accommodate you and your co-survivors. This will make the shelter easier to warm. With adequate shelter and implementation of the other priorities of survival, first aid, water, food and signaling, you should have a successful survival experience with a minimum of discomfort.