Winter Survival

5 WAYS TO LOSE HEAT

Definition: The transfer of heat energy through direct contact CONDUCTION Definition: The transfer of heat energy through direct contact Heat is lost through the hands by contact with metal objects, rock, snow, ice, and liquids. One of the most common ways to get frostbite. Heat is lost through your seat when sitting on cold objects or through your feet when standing.

CONVECTION Definition: The transfer of heat by the movement of gases (wind) The body warms a thin layer of air next to the skin to a temperature nearly equal to that of the skin. If this warm layer is retained close to the body by clothing, we remain warm. If this layer is drawn away by a brisk wind, we feel cold (wind chill factor), and the body tries harder to renew the warm layer. If the clothing is wet, heat loss can be 25 times as great as with dry clothing in calm air.

RADIATION Definition: The transfer of heat energy through space The leading cause of heat loss in almost any situation. Exposed skin is the most vulnerable. An unprotected head and neck may lose up to 50%-75% of the body's total heat production This originated the saying: "When your feet are cold, put on your hat."

EVAPORATION Definition: The change of a liquid to a gas. This requires energy (usualIy in the form of heat) You get cold if you go swimming on a hot windy day. The evaporation of sweat from the skin and the evaporation of water from lungs accounts for a large amount of body heat loss.

RESPIRATION Definition: The inhalation and exhalation of air Inhaling cool air and exhaling warm air accounts for a significant amount of heat loss. This increases rapidly during heavy exertion at low temperatures.

Ways to Prevent Heat Loss To prevent heat loss by respiration, cover the mouth and nose with loosely woven or knit wool To reduce evaporation through excessive perspiration, wear clothes that breathe and are in layers. To avoid heat loss by conduction, use the ensolite pad-and/or other cover between the body and a cold, wet surface. To prevent heat loss by radiation, keep the head, hands, and feet covered. To prevent heat loss by convection, protect the body from the wind.

Winter Clothing Layering For convenience, comfort, function and survival it is essential to dress in layers Layer 1 – Wicking Layer Layer 2 – Insulating Layer Layer 3 – Weatherproof Layer

Wicking/Base Layer This transports moisture (perspiration) away from the skin as efficiently as possible. Polypropylene, Dry-FIT and Cool Max are examples of synthetic wicking fabrics Wool and cotton are no good

Insulating Layer This is where you are trapping body heat, while allowing perspiration to escape. Polar Fleece and wool are your two best choices

Weatherproof/Shell Layer The outer layer is a shell to stop wind and moisture. Breathable. They are not "waterproof" or "water resistant". Gore-Tex or a tight cotton/polyester blend are the best

Wind Chill The wind chill factor is a calculated “temperature” that tells how cold it “feels” outside. It takes into account wind speed and air temperature.

COLD RELATED INJURIES Frostbite – Is the most common cold related injury Hypothermia - Is the number one killer of outdoor recreationalists

The best treatment is prevention. Dress in layers Cover exposed skin Stay Dry! Remember Cotton Kills! It traps moisture against skin promoting loss of heat Hydrate! Our bodies need at least two quarts a day of water When on outings eat foods with high fat and carbohydrate content for high energy Stay out of the wind. There is no such thing as bad weather…just bad clothing!

Frostbite The partial freezing of exposed parts of the body, causing injury to the skin and sometimes to deeper tissues Symptoms Painful, red skin (frostnip) Skin feels cold and numb Whitish / grayish / or yellowish skin color Pain disappears Skin begins to blister

Treatment Swing arms and raise level of activity Place skin next to areas of warmth: Wrist against facial area to warm cheeks Hands in under-arms or groin Give person warm drinks. Dry, gradual warmth is preferred over immersion in warm water.

Remember: The most susceptible body parts: nose, ears, fingers, and toes If not treated promptly, the tissue may be permanently damaged and sensitive thereafter

DO NOT: Rub with snow Rub frostbitten area at all Run under hot water

Hypothermia The body is losing heat faster than it can generate it Hypothermia The body is losing heat faster than it can generate it. When the bodies core temperature drops 2 degrees Celsius Causes Poor physical conditioning Inadequate nutrition. Fats and carbohydrates provide the most warmth Weather (0 - 40 F temperature range where most commonly occurs). Wind - causes convective heat loss Water - causes evaporative cooling - very dangerous Conduction - i.e. sitting on a cold rock, etc. Exhaustion

Treatment Get out of cold and wind Remove wet clothing Keep person moving, exercise. If unable to exercise get them in warm sleeping bag Give warm sweet liquids Passive rewarming may be required. Get person in warm sleeping bag with another warm person, skin to skin contact is best. Do not let the rewarming person become hypothermic themself.

DO NOT: Do’s Place victim in hot shower or bath - can cause aftershock Give alcohol - this increases heat loss Rub or massage extremities Do not rewarm to rapidly. Rapid rewarming causes afterdrop Afterdrop is a condition in which the cool blood in the extremities is circulated too rapidly to the heart. This causes a shock to the heart which can lead to cardiac failure (Ventricular fibrillation.), death. Afterdrop can occur even after the person appears to be recovered, so be alert to it Do’s If person has lost consciousness, warm them externally, maintain their airway, Do not give fluids. You must seek help. Treat their body carefully. Do not jostle or move roughly. Observe vitals very closely - Be prepared to give C.P.R.