Article updated on 21/11/2024
The weather changes quickly in the mountains, as is well known. But even if it is very sunny, the passage of a cloud or the shadow of a peak or a somewhat strong wind, the cold can quickly be felt! And thermal amplitudes are significant in the mountains, especially at altitude. Without reaching extreme temperatures, enduring the cold can be learned quite easily.
The human body does everything to regulate its internal temperature around 37°C. On one hand, it ensures the elimination of excess heat (through sweating), and on the other hand, protection (within certain limits) against cold attacks. The excess heat is expelled by evaporation over the entire body and mainly through the head, hence the need to cover well with a hat or hood in very cold weather.
Conversely, to protect itself from the cold, our body tries to protect the vital organs at the expense of peripheral zones. Blood circulation therefore slows down to the extremities: hands, feet, ears, nose. The extremities are thus the first affected by common conditions: chilblains and minor frostbites. In extreme cases, the body can no longer protect itself against excessive and prolonged cold. Hypothermia, the most serious consequence of cooling, then occurs.
Minor lesions
Frostbite
From mild chilblains to painful frostbite, it is best to avoid them or prevent their consequences.
Chilblains
Who hasn’t felt numbness and then tingling at the fingertips or toes? These first become momentarily numb and pale then eventually warm up and redden thanks to the blood activation that resumes after a while: that is when prickling sensations sometimes quite sharp and irritating appear. Accompanied by slight swelling or cracks, chilblains remain mild for most hikers or skiers. A return to normal occurs within a few minutes, at worst in a few hours.
Chilblains (or frostbites) represent the first degree of frostbite. Some people are more sensitive because they suffer from fragility of the microcirculation as soon as the first cold sensations (acrocyanosis). In this specific case, it is a chronic disease, benign and little known but whose definitive remission can be spontaneous.
More serious lesions
In the second degree of frostbite, clear or blood-filled blisters (phlyctena) can appear. The deep tissues can then necrose, blacken and fall off. The cold acts like a burn and can cause irreversible damage to muscle tissues. A deeply frozen finger, toe, or tip of the ear can die and must be amputated! This is a major risk that mostly concerns athletes facing extreme situations (voluntarily or accidentally).
Prevention
As soon as you plan to go into snowy environments, even for a simple hike in good weather, it is essential to take a good pair of socks, a hat, and a pair of technical gloves. When conditions may be harsher, a second hat and a second pair of gloves as backup at the bottom of the backpack can be very useful. In general, always remember to cover your extremities!
Emergency treatment
In case of quite marked lesions, do not warm the affected part too quickly nor strike it too hard! It is better to warm the affected part gradually by rubbing it. If conditions allow, a warm water bath (at about 37 °C) remains the best solution. Antiseptic without alcohol should then be applied since the risk of infections is increased with this type of lesion. This should be repeated several times a day and, in the meantime, protect the frozen area with a sterile dressing (not too tight).
Hypothermia
Hypothermia corresponds to a very serious state of weakness resulting from a kind of dysregulation of the body’s temperature regulation function. Hospitalized hypothermia cases would represent less than 10% of mountain accidents. In reality, hypothermia is very often the complication of an accident: avalanche, fall into a crevasse, getting lost in a storm or fog.
Three pathological stages are distinguished:
- Mild hypothermia (body temperature has dropped to 35 or 34 °C): the first symptoms are “goose bumps”, repeated and uncontrollable shivering, pale or mottled skin. It has no consequences if it is not accompanied by another trauma (a leg fracture immobilizing the subject, for example) or does not take place in a hostile context (bad weather). The subject must be warmed, covered with dry clothes, given hot drinks, and rapid evacuation should be considered. Alcohol must absolutely not be given!
- Moderate hypothermia (body temperature between 34 and 32 °C).
- Severe hypothermia (temperature has dropped to 32 °C, even 28 °C): In a comatose state, the subject can however be resuscitated under medical supervision.
Buried for nearly an hour under an avalanche, a person whose internal temperature has dropped to 25°C can be resuscitated in hospital and may not suffer aftereffects, but this is not certain! Do not trust appearances if you participate in a victim search operation or an emergency evacuation of an injured person because it is not always too late.
Prevention
It is obvious that we protect ourselves from the cold by being well covered! It is therefore necessary to always anticipate bad surprises and carry warm clothes in your backpack, even if the weather forecast is excellent. Some equipment such as gloves or a hat, for example, must be planned in duplicate, the 2nd set being kept safe at the bottom of the bag (remember to protect them from moisture).
Good physical shape and good morale also help better endure somewhat harsh conditions. If you are lost or trapped in a storm, you need to build an improvised shelter. Igloo (if you master the technique), pits in the snow, among large rocks, under the cover of a tree… In all cases, think about insulating yourself from the ground (at worst, lie down on your bag) and adopt a fetal position. Also remember to signal your presence with a clearly visible mark.
Acclimatizing
It is possible, to some extent, to acclimate to the cold. If you plan to go on an expedition to very cold regions, prepare yourself some time before. Personally, before a trek in Nepal, I used to spend my nights on my balcony in a good sleeping bag. My neighbors laughed well, some thought I was crazy; in any case, I was not cold during the trek, even at -25°C. Another technique is to practice cold water baths for the extremities: soak your hands (and feet) in very cold water until the first pains appear. Repeat every day and after some time you will have acquired dexterity and resistance to the cold that you will appreciate.
