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Avalanche danger is the potential for an avalanche, or avalanches, to cause damage to something of value (Statham et al., 2018).
The avalanche danger level is a function of snowpack stability, the frequency distribution of snowpack stability, and avalanche size for a given unit (area and time). The European Avalanche Danger Scale has five levels: 5 – very high, 4 – high, 3 – considerable, 2 – moderate, 1 – low.
Extraordinary avalanche conditions
Numerous very large and often extremely large natural avalanches can be expected, even in moderately steep terrain.
Very rarely forecast.
Very dangerous avalanche conditions
Triggering is likely, even from low additional loads, on many steep slopes. In some cases, numerous large and often very large natural avalanches can be expected.
Typical danger signs:
Widespread recent avalanche activity, cracking, “Whumpf” sounds.
Remote triggering of avalanches is typical.
Forecasted only on a few days throughout the winter.
Around 10 % of avalanche fatalities.
Dangerous avalanche conditions
Triggering is possible, even from low additional loads, particularly on the indicated steep slopes. In certain situations some large, and in isolated cases very large natural avalanches are possible.
Typical danger signs:
Recent avalanche activity, cracking, “Whumpf” sounds.
Remote triggering of avalanches is typical, especially if Persistent weak layer is one of the avalanche problems.
Forecast for around 30 % of the winter season.
Around 50 % of avalanche fatalities.
Heightened avalanche conditions on specific terrain features
Triggering is possible, primarily from high additional loads, particularly on the indicated steep slopes. Very large natural avalanches are unlikely.
Typical danger signs:
Often you get no danger signs, but that does not necessarily mean it is safe. Pay extra attention if Persistent weak layer is one of the avalanche problems.
Forecast for around 50 % of the winter season.
Around 30 % of avalanche fatalities.
Generally stable conditions
Triggering is generally possible only from high additional loads in isolated areas of very steep, extreme terrain. Only small and medium natural avalanches are possible.
Typical danger signs:
Rarely any danger signs.
Forecast for around 20 % of the winter season.
Around 5 % of avalanche fatalities.
