Avalanche risk in Switzerland

Avalanche Risk Scale

Risk level

Snow stability

Avalanche Risk

Recommended action in back country

Low

Snow is generally very stable.

Avalanches are unlikely except when heavy loads [2] are applied on a very few extreme steep slopes. Any spontaneous avalanches will be minor (sluffs). In general, safe conditions.

Virtually no restrictions on off-piste & back-country skiing & travel.

Limited

On some steep slopes the snow is only moderately stable [1]. Elsewhere it is very stable.

Avalanches may be triggered when heavy [2] loads are applied, especially on a few generally identified steep slopes. Large spontaneous avalanches are not expected.

Use caution in steeper terrain.

Medium

On many steep slopes [1] the snow is only moderately or weakly stable.

Avalanches may be triggered on many slopes even if only light loads [2] are applied. On some slopes, medium or even fairly large spontaneous avalanches may occur.

Be increasingly cautious in steeper terrain.

High

On most steep slopes [1] the snow is not very stable.

Avalanches are likely to be triggered on many slopes even if only light loads [2] are applied. In some places, many medium or sometimes large spontaneous avalanches are likely.

Travel in avalanche terrain is not recommended. Safest travel on windward ridges of lower angle slopes without steeper terrain above.

Very High

The snow is generally unstable.

Even on gentle slopes, many large spontaneous avalanches are likely to occur.

Travel in avalanche terrain should be avoided and travel confined to low angle terrain well away from avalanche path run-outs.

[1] Stability:
Generally described in more detail in the avalanche bulletin (regarding the altitude, aspect, type of terrain etc.)

[2] additional load:
heavy: two or more skiers or boarders without spacing between them, a single hiker or climber, a grooming machine, avalanche blasting.
light: a single skier or snowboarder smoothly linking turns and without falling, a group of skiers or snowboarders with a minimum 10m gap between each person, a single person on snowshoes.

Gradient:
gentle slopes: with an incline below about 30°.
steep slopes: with an incline over 30°.
very steep slopes: with an incline over 35°.
extreme steep slopes: extream in terms of the incline (over 40°), the terrain profile, proximity of the ridge, smoothness of underlying ground.