Cold Weather Injuries

In any cold weather survival situation, it's important to watch out for--and know how to treat--the four major types of cold weather injury.

HYPOTHERMIA  (read more on causes of heat loss)

• Cause: Hypothermia occurs as a result of abnormally low body temperature. In cold weather, this often occurs when a person wears inadequate clothing or gets wet.
• Signs and symptoms: Uncontrollable shivering, slurred speech, abnormal behavior, fatigue and drowsiness, decreased hand and body coordination and weakened respiration and pulse.
• Treatment: Prevention is the best medicine: Avoid wind and wear layered clothing and a hat, gloves and good insulated boots. If symptoms of hypothermia occur, get out of the wind, and change into dry clothes including a hat, socks and gloves. If you have a sleeping bag or a blanket, use it as another layer of warming insulation. If possible, consume warm fluids and eat carbohydrates. If you don't have a change of clothes, warm fluids or a fire, wring the moisture out of your clothes, get out of the wind and flex your big muscles (thighs, etc.) to help generate body heat.
• Worst Potential Outcome: Death.

FROSTBITE

• Cause: Frostbite occurs when skin is exposed to temperatures below its freezing point.
• Signs and symptoms: Superficial frostbite causes skin to feel cold, tingly and painful and to appear white or grayish in color. As frostbite begins to affect deeper layers of tissue, the skin swells, loses feeling and becomes hard to the touch. Blood-filled blisters form.
• Treatment: Avoid frostbite by protecting vulnerable areas--especially fingers, toes, ears and facial skin--with appropriate layered clothing (a moisture-wicking layer like polypropylene, followed by an insulating layer like wool or fleece and topped with an outer wind protective layer like Gore-Tex). If superficial frostbite occurs, re-warm the affected part with your own body heat (for example, hands should be placed in the armpits; feet on another person's abdomen). If deep frostbite occurs, do not attempt to re-warm skin! Seek immediate medical attention.
• Worst Potential Outcome: Tissue death and amputation of affected area.

IMMERSION INJURY (TRENCH FOOT)

• Cause: Immersion injury occurs when feet (or hands) are exposed to cold and damp conditions for an extended period of time.
• Signs and symptoms: Painful, swollen, wrinkled and often red-colored skin on the feet or hands ("dishpan" appearance). In severe cases, swelling increases and blisters may form.
• Treatment: To avoid immersion injury, change wet socks immediately, wear loose and layered clothing (not tight) and massage feet and hands at regular intervals to increase circulation. If an immersion injury develops, treat by gently drying (pat dry) the affected body part, elevating it and getting out of the cold.
• Worst Potential Outcome: Blisters, sores, gangrene and amputation of affected area.

SNOW BLINDNESS

• Cause: Occurs when eyes are exposed to ultraviolet (UV) rays reflected off of snow and ice.
• Signs and symptoms: Bloodshot appearance, tearing, sensation of grit in the eyes, light sensitivity and headaches.
• Treatment: To avoid snow blindness, wear sunglasses that block 100 percent of UV rays. If snow blindness occurs, avoid further exposure and apply a cool, wet compress to the eyes. Take a non-steroidal anti-inflammatory, like ibuprofen or aspirin, to help control pain.
• Worst Potential Outcome: Permanent blindness.

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THE FIVE CAUSES OF HEAT LOSS

Hypothermia is the biggest threat to a person's survival in cold weather. However, this silent killer can be avoided if you learn to recognize and guard against the five major causes of heat loss.

Radiation: This is the transfer of heat from your body to the environment. The colder it is, the more heat is lost. The head, neck and hands are most at risk for heat loss from radiation. Wearing layers of protective clothing on these sensitive areas can significantly slow the process.

Conduction: Body heat is lost through conduction when the body comes in contact with cold objects. The colder the object is, the greater the heat loss. This poses a significant problem when a person's clothing is wet or one is submerged in cold water. When contact with a cold item is inevitable, use a foam pad or similar item to create a barrier between your body and the object. If clothes get wet, immediately remove and change them, if possible. If not, it is important to wring out as much of the moisture from your clothing as possible.

Convection The body loses heat when air movement across the skin carries it away. This happens with any movement (walking, running, etc.) and when your body is exposed to wind. Convection heat loss can be eliminated by staying still and protecting yourself from the wind. Wearing loose layers with an outer nylon shell (like one made of Gore-Tex) helps trap warm air next to your body and decreases the impact of convection heat loss.

Evaporation: Body heat is lost through evaporation when moisture from your skin (perspiration) evaporates, so it's important to minimize sweating in a cold weather survival situation. If you start to sweat, slow down your movement or stop moving altogether. Add or remove clothing layers as needed to stay warm without sweating.

Respiration: The last type of heat loss occurs when you breathe, as the body warms inhaled cold air en route to the lungs. The colder the air is, the more heat that is lost. To decrease respiratory heat loss, cover (or encircle) your mouth with an insulating layer of clothing. This layer will trap air, allowing it to warm slightly before you breathe it in.