Avalanche Danger Rating

The regional avalanche forecast includes and avalanche danger rating.  It is issued by local meteorological experts and is there to provide you with specific indicators of likely risk.  Whereas the local forecast is created by the piste patrol based on their experience of the mountain.  There may be a difference.  I would be guided whichever is the highest level warning.

The local forecast is created early in the morning and will be published on noticeboards around the ski area.  The regional forecast is created the prior evening and published on the web.  Links to the bulletins are here

These avalanche forecasts tell you about snow stability:  reading the avalanche forecast and the avalanche danger rating is essential to understand the risks for the day.  It includes a danger rating.  To use the avalanche forecast, you must understand the definition for the ratings.   This table is carefully worded, read it in detail and this will help you to know how to conduct yourself off piste.

Click on the sound buttons to hear Henry talk about each of the danger levels


Danger/Risk level Listen Snow Stability Probability you can trigger an avalanche
1) lowavalanche danger rating, level 1, low

Very few unstable slabs. The snow pack is well bonded and stable in most places [1]. Triggering is possible generally only with high additional loads[2] on a very few very steep slopes[4]. Only a few small natural[6] avalanches(sluffs) possible.
2) moderateavalanche danger rating, level 2, moderate

Unstable slabs possible on some steep[3] slopes[1] Triggering is possible with high additional loads[2], particularly on the steep[3] slopes indicated in the bulletin. Large natural[6] avalanches not likely.
3) considerableavalanche danger rating, level 3, considerable

Unstable slabs probable on some steep[3] slopes [1]. Triggering is possible, sometimes even with low additional loads[2]. The bulletin may indicate many slopes which are particularly affected. In certain conditions, medium and occasionally large sized natural[6] avalanches may occur.
4) highavalanche danger rating, level 4, high

Unstable slabs likely on many steep [3] slopes Triggering is probable even with low additional loads[2] on many steep[3] slopes. In some conditions, frequent medium or large sized natural[6] avalanches are likely. Triggering and exposure to avalanches is possible on many lower angle slopes [1].
5) very highavalanche danger rating, level 5, very high

The snowpack is weakly bonded and very unstable Numerous large natural[6] avalanches are likely to reach low angle slopes. Extensive safety measures (closures and evacuation) are necessary. No off-piste or back country skiing or travel should be undertaken due to a high risk of exposure.

Notes

  1. These places or slopes are generally described in more detail in the avalanche bulletin (e.g. altitude, slope aspect, type of slope/terrain, etc.).
  2. High additional load is group of skiers, piste-machine, avalanche blasting.  Low additional load is a single skier, walker.
  3. Steep slopes are those with an incline of more than 30 degrees
  4. Steep extreme slope are those which are particularly unfavourable in terms of the incline, terrain profile, proximity to ridge, smoothness of underlying ground surface.
  5. Aspect is the direction the slope faces. e.g. if you have your back to the slope and you faces south,  the aspect is south facing
  6. Natural means without human assistance.