Avalanches – The Basics

Avalanches mtxplore

by Geir Mjosund 20/12/2014

Avalanches are fascinating. Meanwhile the enormous forces that can be triggered by something as light as snow is frightening. The horror scenario is to be buried under several tons of snow, which quickly becomes hard as concrete.

Avalanches – The Basics

The assessment of avalanches requires much experience and local knowledge. On winter trips it can also take a long time before you meet other people. Traveling with others can therefore be vital.

Important equipment in the backpack

Shovel, probe, first aid kit, sleeping mat, warm clothes and a bivy bag is the most effective aids in the winter mountains. If you bring this equipment it can save you in many situations.

In addition you should have an beacon if you and your Buddies are traveling in steep terrain.

The safest way to avoid avalanches is evading dangerous places, like walking on a ridge instead.

To avoid Avalanche

  1. Avoid terrain steeper than 30 degrees: Slopes steeper than 30 degrees are often an avalanche hazard (Further down the page: Measure the slope with poles or by using a compass). Even small slide sides of 7-10 meters can cause a serious avalanche. You should stay away from the leeward sides that are smooth and snowy, although they did not appear to high. In terrain flatter than 30 degrees you can almost always travel safely from an avalanche.
  2. Avoid slopes that are sheltered from the wind: Here heavy snow-packs gather. Slabs can be identified by looking at the cornice formed on top of the steep areas. Be aware that it can form slabs in several directions if the wind has led snow-packs in different directions during the winter.
  3. Keep a good distance from mountain sides where it can go avalanche: Avalanche can under optimum conditions be remotely released and move far out of the mountain side where the avalanche started. A rule of thumb is that a avalanche under optimal conditions can move three times so far in the horizontal direction in the vertical direction. If the avalanche starts 50 meters up a mountain side it could theoretically reach 150 meters out in from the mountain side.
  4. Be confident, follow the ridge: On the mountain ridges snow will blow away. Even on winters with heavy snow you will easily find mountain ridges which is almost free of snow.
  5. Avoid canyons: Canyon valleys often catches a lot of snow, and even shallow canyons under 10 meters can pose a real danger.
  6. Check the avalanche forecasts and listen to local knowledge: Remember that avalanche danger increases with wind and precipitation, when snow gathers and when the temperature rises.

Measure the slope with your poles

To measure whether a slope steeper than 27 °: Keep a ski pole perpendicular to the ground. The second rod positioned horizontally with the center handle on the vertical. The angle must be 90 ° (a right angle).

If the rod tip on the horizontal rod ranks right away to the ground, the angle about 27 °. If there is insufficient space for the whole rod length, the slope steeper than 27 °.

Measure the slope with the aid of a compass

Get a compass with a protractor. You can measure slopes easily from side or front by aiming towards the highest steep point. Read the angle by means of the mirror.

If you are caught by avalanches

  • Try to get away by slipping diagonally out of the avalanche.
  • If you can not get away, try to get rid of skis and poles. They will pull you down in the Avalanche.
  • Try your best to keep your mouth free of snow and try if possible to get an air pocket in the snow by holding your arms in front of your face.

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If someone else is taken by avalanche

Friends are vital. Opportunities to find burials alive is certainly the greatest during the first 15 minutes after an avalanche has passed.

Therefore stay focused and effective in the phase after avalanche has gone, so you do not play out important time.

  • Check first if it can go new avalanches.
  • Note the place where people was last seen. Use this as a starting point where you choose to start the search.
  • Started exploration immediately.
  • Go over the avalanche and see if there sticks up some equipment.
  • Insert the probe rod / ski pole deep into the snow where it is most likely to find someone.
  • Avalanche shovels and probe rod is the most effective aids for rescuing.
  • Avalanches requires training. Both the burials and several of the party must have used this equipment themselves.
  • It is important to notify an organized rescue quickly, call local emergency. It may take several hours before rescue reaches the accident.
  • Most possible must be left in the avalanche area to look in the start-up phase of the search for survivors.

Search Equipment

Shovel, probe and avalanche transceiver is the most effective aids for rescuing.

Electronic avalanche transceiver requires training. Both the burials and several of the party must have used this equipment themselves.

Some Avalanche and Weather Links

YR – Weather Report

SLF – Swiss Alpes Avalanche Report

Meteo – French Alpes

Mountain Forecast – Weather Reports from most mountains

As usual, if you have any questions, do please contact me.

20/12/2014 / mountains / 8000ers / avalanches / mtxplore.com