Winter Survival – How to avoid an Avalanche

It may seem a little strange to publish a post about avalanches just as spring is about to appear in the northern hemisphere. However there remains a risk of an avalanche for those heading into the backcountry where snowfields still cling especially in sheltered areas.

The Mont Blanc massif near Chamonix in the Rhône-Alpes region of France on Mallory on Travel, adventure, adventure travel, photography

An adventure playground

Spring avalanches are often of the wet slab type but when fresh snow has recently fallen and lays on top of existing the snowpack. The warm weather that usually accompanies spring can greatly increase the risk of a slide.

It is also slightly macabre fact that due to the difficulty in finding victims their bodies often aren’t discovered until the snow melts in the spring.

The Brevent in the Mont Blanc Massif which surround Chamonix in the Rhone-Alpes region of France on Mallory on Travel, adventure, adventure travel, photography Iain Mallory-300-25 chamonix

Be aware of changing weather conditions

All outdoor pursuits enthusiasts, mountaineers, ski-tourers and back country snowboarders should be suitably equipped and aware of how to move in avalanche terrain when heading into the mountain environment where snow conditions exist. In common with most hazards avoidance is always preferable to dealing with the consequences so it’s important to understand some of the risk factors and types of avalanche.

The peaks of the Mont Blanc Massif which surround Chamonix in the Rhone-Alpes region of France on Mallory on Travel, adventure, adventure travel, photography Iain Mallory-300-27 chamonix

Ice and cloud

Risk Factors

Slope – Avalanches on shallow slopes below 20° or steep ones above 60º are extremely rare as the angle is either too low to produce sufficient momentum or too steep for snow to hold to. Most avalanches occur on slopes between 25º and 45º.

The Marmolada in Val Gardena the Dolomites region of the italian South Tyrol on Mallory on Travel, adventure, adventure travel, photography DPP_0077_edited-1

Snowfields on the gullies of the italian Dolomites

Slope Shape – The shape of a slope can have an effect on the possibility of an avalanche; the back of a concave slope is likely to be compressed and relatively stable. However at the top of a convex slope the snowpack can be stretched and under pressure greatly increasing the chance of a release.

Weather conditions – 48 hours after a snowfall is the highest risk factor, longer in cold conditions. Long periods of cold weather will provide a stable snowpack which will remain unchanged for several months. Periods of warmer weather will cause changes in the structure of the crystals in the layers of snow. Melt-freeze can substantially increase the risk of an avalanche during the melt phase and especially if combined with rain.

Types of Avalanche The main forms that an avalanche can take are as follows:

Slab – Shattering like a pain of glass this is the big killer, often know as “The White Death”, often the whole snowfield slides as one and anybody caught on it is in for the ride for their life. There is a visible fracture line and half football field sized slabs up to 3 feet thick can travel at speeds of up to 130kph/80mph can be reached. Hard slab avalanches are one of the greatest hazards of the mountain environment, often formed by strong winds on lee slopes. Appearing chalky and dull, it often ‘squeaks’ underfoot, a sign of the inherent weakness between layers and immediate escape is highly recommended.

Dry-snow – This type of avalanche starts from a single point and can fan out rapidly, they are often small ‘sluffs’ but larger ones can knock down houses. They generally travel at speeds below 65kph/40mph above this they often become airborne.

Snow patrol in Chamonix near Mont Blanc, France on Mallory on Travel, adventure, adventure travel, photography Iain Mallory-300-26 chamonix

Avoiding the free public transport is a good idea

Airborne – The most destructive form of avalanche, in alpine regions they can be huge and reach speeds of up to 290kph/175mph. Everything is cleared from their path, nothing is safe. Trees are felled like matchsticks, houses toppled like dominoes even whole forests and towns disintegrate in their wake. An airborne avalanche is one of nature’s most spectacular events and anybody that has witnessed one even from a distance never forgets the experience.

Wet – Most common in spring or after a period of thawing, as snow melts and water percolates between the layers it provides a perfect frictionless base on which the upper layer can slide. They can be in loose or slab form and travel slowly or quickly, they are also more difficult to trigger which is why they don’t account for as many fatalities. Don’t be fooled however they can be fatal and once stopped they set like concrete making escape difficult.

Cornice – Often formed by wind they can collapse due to an increase in temperature or due to their own weight and can occur in periods without any snowfall.

Avoiding an avalanche is usually a combination of good planning, mountain craft and common sense, here are some tips:

Pre-trip planning

  • Be aware of the weather conditions, check forecasts, recent history and avalanche warnings for the area. Be thorough and research fully.
  • Plan the route carefully, check for hazard areas, leeward slopes and terrain, where possible avoid high risk sections of the proposed route.
  • Include escape routes and have a plan of action if the worst happens.
  • Ensure you have all the necessary safety equipment, working correctly and know how to use it properly. The following is the minimum:

    A BCA avalanche beacon or transceiver on Mallory on Travel, adventure, adventure travel, photography 220px-LVS-Tracker-DTS

    An avalanche tranceiver LVS-Tracker

    • Avalanche transceiver
    • Snow shovel
    • Avalanche probe
  • Be prepared to change plans if the risk is high.

On the Mountain

  • Never travel in avalanche prone areas alone.
  • Ensure all transceivers are working and switched to send.
  • Be aware of the conditions and be prepared to change the planned route if the risk appears to be high.
  • Stops must be away from any risk factors and campsites in known safe areas.
  • Maintain a sensible distance between individuals, minimising the risk to one person at a time.
  • Prior to crossing any slope assess the risk factor, if necessary dig a small snow pit and test the cohesion between layers. Learn how to conduct a shear test such as the Rutschblock test.
  • Cross the slope one at a time, assess any run out in case of the worst and if necessary protect with a rope, belaying from a ‘bombproof’ anchor point.
  • Prior to crossing loosen rucksack straps and unbuckle the waistbelt. Do up the jacket and wear a hat and gloves.

If the worst happens

  • Attempt to escape to the sides or find a natural shelter such as a large boulder.
  • Discard any loose gear such as ice axe or poles.
  • Shout once, then close your mouth, cover your nose and attempt to ‘swim’ on the surface.
  • If you realise the avalanche is coming to an end make a supreme effort to reach the surface.
  • The majority of fatalities are from asphyxiation, the victims own breath forming a ‘death mask’ as it freezes, try to create a breathing space. Ascertaining which way up you are is the first priority, dribble some spittle and if it runs down your chin you are upright, if not oops! Attempt to dig in the opposite direction the spittle ran.

    Avalanche prone slopes in the Mont Blanc massif near Chamonix in the Rhône-Alpes region of France on Mallory on Travel, adventure, adventure travel, photography Iain Mallory-300-22 chamonix

    On the piste in Chamonix

Witnessing and rescue

  • The chances of a successful rescue reduce dramatically after the first hour of avalanche so it is imperative to stay calm and attempt a rescue as quickly as possible.
  • Attempt to follow the victims route and establish the last place they were seen, then try to work out where they may have eventually come to rest.
  • Assess any residual risk, do not become a victim too.
  • Establish a search plan, potential escape routes if required and brief other search companions.
  • Make an initial visual search of the area, looking for limbs, items of equipment or clothing on the surface.
  • Remain alert and listen carefully for any cries for help.
  • Employ your detailed search plan using avalanche probes and transceivers, now switched to receive.
  • Be prepared to provide any rescue team with any details that may assist them, including where the victim was avalanched and last seen. Inform them where has already been searched.

To Sum Up

  • Lee slopes between 25º and 45º are most prone.
  • Increases in temperature will also increase the risk.
  • Check the recent weather history, the forecast and avalanche risk warning.
  • The first 48 hours after a snowfall is the most at risk period.
  • Plan the route carefully and be prepared to change plans.
  • Be properly equipped and know how to use the equipment.
  • Remain alert of risk factors at all times.
  • The chances of survival of a trapped victim are greatest during the first hour.

*The author (me) is a qualified winter mountain leader and avalanche specialist.

Avalanche prone slopes in the Mont Blanc massif near Chamonix in the Rhône-Alpes region of France on Mallory on Travel, adventure, adventure travel, photography Iain Mallory-300-12 (2)

Alpinists playground

1

Comments 2

  1. Leigh

    I’ve taken avalanche courses in Colorado where there’s a high incidence of avalanche deaths. I’ve also skied enough in avalanche country to know that it just makes me too uncomfortable. There is a science to predicting avalanches for sure but I feel like it’s a crap-shoot when you’re in avalanche country and I’m just not prepared to take that risk. I love to backcountry ski but now I stick to slopes that are as risk free as you can get.

    Good info in this post too.

    1. Post
      Author
      Iain

      Great idea Leigh, I believe anybody travelling into backcountry where there is the possibility of avalanche should take a course. Knowing how to avoid a release and what to do if the worst happens is a sensible way to go and would probably avoid numerous incidents or fatalities.

Leave a Reply

Your email address will not be published. Required fields are marked *