Frostbite - What it is, and How to Avoid It

As the Beast from the East envelops the UK and mountain forecasts talk about -10'C on the summits and -30'C windchill in the winds, the risk of frostbite in the mountains has increased dramatically. Here is a quick article on what frostbite is, how to try to avoid it and what to do if the worst should happen and you get it. You do not have to be climbing on Everest for frostbite to strike!

He loves his gloves  © Dan Bailey
He loves his gloves
© Dan Bailey

What is frostbite?

Frostbite is when the fluid in your cells freezes and swells. This puts pressure on the cell membranes and as a double whammy chemicals are produced which can permanently damage the tissues.

Frostbite usually affects the extremities such as the fingers, ears, toes and nose and another rather essential part of the anatomy to men (as Mike Stroud can testify to from his Antarctic expedition!) However it can occur anywhere and in one case two winters ago, a fellrunner in the Peak District running in a blizzard got frostbite to his legs which stopped at the ankles where his feet were protected by his footwear.

There are different levels of frostbite and from the past when we tended to talk about Frostnip, superficial frostbite and deep frostbite, frostbite now is normally measured in degrees.

First degree frostbite: this is also known as Frostnip and is when the top layer of the skin freezes. It does not cause cellular degeneration. It can feel numb, itchy or like the skin is taut. It may look whitish and can be warmed easily by warm contact from other warm tissue such as hands. Often it occurs in cheeks or other exposed skin.

Second degree frostbite: often also called superficial frostbite. However, do not be fooled. This is frostbite and it is serious! This can cause some permanent damage and needs to be treated as frostbite. Here all the layers of skin are affected resulting in clear blisters when the frostbite thaws. The skin is hard and white but usually there are no major ill effects so long as it is treated correctly, although someone may find that the affected area might lose some sensation and it will be more prone to frostbite in the future.

Third and fourth degree frostbite: (deep frostbite) the damage here goes down into the muscle and even the bone in the worst cases. This causes permanent damage and although the area may survive there is tissue damage and sometimes the tissue will die through lack of blood supply and oxygen. Large dark blisters may form although sometimes the limb just looks dessicated.

Causes and prevention:

  1. Exposure: if skin is exposed to bitterly cold below freezing temperatures then frostbite can occur within minutes. In particular windchill factor has a large part to play.

What this means for hill walkers and winter climbers:

  1. In winter always make sure you drop the faff factor. Have gloves at hand (in pockets, not buried in stuff sacks deep within your rucksack!)
  2. Get used to carrying out tasks in gloves. E.g. Putting crampons on and fastening crampon straps, doing up zips etc.
  3. If you can't manage these tasks with big gloves then at least always have a small thin pair of thermal gloves (Merino or synthetic) which keep your skin covered and try to keep the time your hands are in these alone to an absolute minimum.
  4. Minimise duration of food stops and keep everything you need handy.
  5. Have plenty of spare pairs of gloves in particular so that if a pair get soaked they can be replaced by a dry pair. It is worth carrying waterproof outer mitts to keep gloves dry while not carrying out intricate tasks.

Gloves are easily lost, so fit them with a lanyard or elastic loop   © Lorraine McCall
Gloves are easily lost, so fit them with a lanyard or elastic loop
© Lorraine McCall

In winter it's easier to lose gloves in the windier conditions and so spare pairs are essential. A few years ago there was a case of frostbite on the Carneddau in Snowdonia. A climber on the Ysgilion Duon (Black Ladders route) lost a glove on an early pitch but carried on climbing. He got frostbite in the hand as a result of the exposure.

  1. Constriction: frostbite is far more likely to occur if circulation is poor. This means any tight or constrictive clothing and footwear which slows or prevents blood flow to extremities can cause frostbite.

What this means for hill walkers and winter climbers:

  1. Make sure your winter boots are large enough. Cold feet can be a sign of your footwear being too tight. Sometimes this is because the boots were not fitted correctly (danger of buying boots off the internet!) or because people may put two pairs of socks on for insulation and so their feet get crushed. If you find your feet are cold, get your boot size and fitting checked out. When I was on my Winter Mountain Leader assessment, a member of our group got frostbite because their boots were too tight. Not good! Quite a few of us who are active and spend a lot of time on our feet for work find that our feet spread which means you may still find your feet 'grow' as an adult and you may have to go up a size or two.
  2. Avoid wearing clothing e.g. gloves which are too tight. I often buy a larger size for my winter gloves as tight gloves equals cold hands. Mitts can be even warmer although less dexterous and I do still use my old Dachsteins!
  3. Be aware that constriction can also be caused by clutching things such as ice axes and walking poles as the blood is being squeezed out of the hands. Wear decent gloves when using these!

Increased risk: anyone with a circulation disorder is more likely to develop frostbite e.g. Raynaud's, diabetes, so prevention and management is even more important.

Nigel Vardy, AKA Mr Frostbite on UKC. An Alaskan storm and severe frostbite took his fingers and toes overnight.  © Nigel Vardy
Nigel Vardy, AKA Mr Frostbite on UKC. An Alaskan storm and severe frostbite took his fingers and toes overnight.
© Nigel Vardy


So if the worst happens and you end up with Frostbite, what should you do? Well, there are a set of 'Do's and 'Do nots'


  • Do reheat quickly using warm (hot) water around 40 - 42'C. (Use the elbow test for temperature). Be warned, the thawing process is extremely painful. Think of the worst hot aches you have ever had and times it by ten! Painkillers will almost certainly be needed!
  • Do remove jewellery. The frost bitten area may blister and swell and jewellery will then just act to constrict circulation.
  • Do take 75 mg Aspirin daily to help circulation. Ibuprofen every 8 hours helps to inhibit potentially damaging toxins. Obviously if there is a reason why you can't take these drugs, then ask for medical advice.
  • Do dress the frostbite with loose non-adherent dressing. Aloe Vera gel has also been proved to be helpful with frostbite so the dressing or the limb can be smeared with the gel. It is worth splinting as this also prevents you from using the damaged limb.
  • Do avoid putting any pressure on the damaged area as cell membranes may be damaged or rupture.
  • Do get it checked out in hospital ASAP. They will be able to tell you how severe the frostbite is and treatments required.
  • Do take as many photos as possible (not just from ghoulish interest but because it does allow the medics to see how serious the frostbite is, both by the original frozen area and by how the frostbite develops over time). Of course your friends will also love to hate your Facebook update photos as well!
  • DO look at the BMC website Or


  • Do not Rub to rewarm: this can break cell membranes and make the damage far worse.
  • Do not rewarm unless you can guarantee the frozen part is not going to freeze again. So if you are snow-holing on the Cairngorm Plateau and discover that you have frostbite, wait until you are safely off the hill and back in warm accommodation before you try to thaw the frostbite.
  • Do not use dry heat to rewarm such as a radiator or heat from a fire. Wet heat is better for frostbite.
  • Do not pop any blisters yourself. Let the hospital decide how they are going to treat your frostbite.
  • Do not use the damaged limb. If it is a foot, avoid walking or putting pressure on it.

So prevention is better than cure! Avoid constrictive and tight clothing, avoid having exposed extremities. And get out there and enjoy these amazing winter conditions we are having!

Helen Howe head shot  © Helen Howe

About Helen Howe

Helen runs Snowdonia First Aid with her husband Steve.

Each have over twenty years of Scottish winters and are qualified Winter and International Mountain Leaders. They run Outdoor First Aid courses and Mountain Leader Training and Assessments as well as mountain and hill skills courses. This winter Helen and Steve are running Winter Skills courses both in Snowdonia and Scotland.

Helen is also a qualified Mountain Rescue Dog handler who has trained three SARDA dogs. Both she and Steve are active members of Llanberis Mountain Rescue Team and have served on the Medical and Training Sub committees running some of the team's winter training.

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