• Preventative measures
• Clothing
• Identifying factors of risk
• Shelter
• Hypothermia
• Frostbite

We've all heard the story of the party of school children dying of exposure near Ben MacDhui. Cold is the fundamental killer in most navigation tragedies and a fair proportion of avalanche disasters.

Injury from the cold is perhaps one of the backcountry dangers which many do not expect, and as such it can easily catch you out.

The human body must maintain a heat of +37°c to operate. We all know body heat is generated from food, but also in a cold backcountry environment this heat can be lost through heat transfer.

For proper information on staving off cold, and what to do if the worst comes to the worst, you should seek instruction from qualified instructors.

Preventative measures
The human body has various ways of responding to cold temperatures, such as shivering. However, the most important methods of staying warm in a cold backcountry situation are through clothing and shelter. Learn to spot early symptoms of a potential cold related problem, assess the situation, and react promptly.

Clothing
Use different layers of thin clothing, rather than few thick pieces. This allows better heat control. Each layer must be of a wicking fabric, to keep moisture away from the body and keep you dry. You should consider wearing, each time, a base layer, a mid layer, and a shell layer. A hat, gloves/mitts, boots, socks and goggles are, of course, essential. Consider taking some spare clothes, incase temperatures are colder than anticipated, or incase of a scenario such as being immersed in cold water. In such situations, a change of clothing is essential.

Identifying factors of risk
There are a variety of factors, some environmental, but some personal.

Environmental factors:
- Air temperature
- Damp
- Cold water immersion

Personal factors:
- Inactivity
- Hunger or thirst
- Fatigue
- Physique
- Inadequate clothing
- Injury
- Illness

Shelter
Taking shelter is all about reducing the risk of hypothermia or frostbite by removing the environmental factors. A group shelter may be a handy device to carry, as it can be set up quickly and offers a large amount of protection.

For longer-term shelter, consider building a snowhole or snow cave. If you are unfortunate enough to get caught overnight, or caught in seriously bad weather, this may be a realistic option. Choose a site free from avalanche danger - ideally a site with a drift or bank of snow, and make sure that the entrance will be facing away from the prevailing wind. Don't forget to stick a ski pole or avalanche probe through the roof of your shelter to keep air circulation. Check the air hole at regular intervals also, to ensure that snow does not drift into it. It can be cleared by wiggling the ski pole/probe. It might be an idea to have a raised sleeping platform, so that you nearer the warm air in the upper part of the shelter. You should ideally have had instruction or experience in building a snowhole/snowcave before, so will be aware of how to construct one safely and efficiently.

Hypothermia
This occurs when the body cannot generate enough heat to prevent the body core (torso area) from cooling down. A loss in temperature of just 2°c, to bring the core temperature down to +35°c brings about the onset of mild hypothermia. In such cases, a victim will begin to slow down, shiver, feel cold, become confused, apathetic, clumsy, and lose co-ordination. Their speech may become slurred and perhaps they might even change in character. Further core temperature cooling leads to profound hypothermia at +32°c where shivering will stop, and the pulse and breathing will slow. Further cooling will result in unconsciousness and, ultimately, death.

In cases of mild hypothermia, get shelter from the weather to reduce the cooling effect. Insulate the victim from the ground, and change wet clothing for dry clothing. Get the victim into a bivy/emergency bag - this will allow the victim to use their own body heat to re-warm. If they are conscious, offer food and drink - this will help with the re-warming process. External heat can be applied, but do not, under any circumstances, offer alcohol.

In cases of profound hypothermia, get shelter from the elements to reduce the cooling effect. Insulate the victim from the ground, and change wet clothing for dry clothing. Check the victims ABC, checking for pulse every 3 minutes, and remembering that the pulse can be slow. Slowly re-warm the victim, through measures such as applying hot drinking bottles (insulated to prevent burns) to the neck, armpits, and groin. Do not apply heat to the limbs, as this will cause cooled blood to travel back into circulation, causing further cooling. Warm the surrounding environment - if in a group shelter, a stove will help. If the victim is not breathing and has no pulse, CPR may not be effective, and there is a chance of cardiac arrest. If CPR is not given, the heart may recover on its own as the body is re-warmed.

If hypothermia is caught and treated quickly, no ill-effects will be suffered. However, one must be vigilant to prevent a minor situation turning into a serious one. Hypothermic victims should have 48 hours rest, to allow the body and heart to recover.

Frostbite
In mild cases, this is known as frostnip. Frostnip is a superficial freezing of tissue, whereas frostbite sees deeper freezing of tissue. This is most common in extremities, such as toes, nose and fingers. In severe cases, it can require amputation. This is a real risk in cold situations, particularly with constrictions in blood flow, caused by tight fitting boots etc, prevents the amount of blood circulation. Danger signs are body parts feeling painful, the loss of feeling in extremities such as hands or feet, areas of the body looking pale or, in extreme cases, purple.

In such cases, get out of the area as quickly as you can, and do not attempt to thaw frozen tissue - this will do more damage in the long run. Proper treatment must be done at a hospital.