Avalanches are sliding or falling snow masses. They are caused by instabilities in the snowpack. Avalanches occur mostly in steep terrain. The formation of avalanches is facilitated by heavy snowfall, strong wind or a significant rise in temperature. Avalanches can be released naturally (without human intervention) or by people. In 90 percent of cases, avalanches are triggered by the victims. In settlements and on transportation routes, the local authorities ensure the safety of the population. Those who engage in winter sports beyond the boundaries of marked and open pistes, or cross-country ski or hiking trails, are responsible for their own safety.

Meaning of danger level 1 (no or low danger)

Avalanches can only be triggered in isolated cases on extremely steep slopes (steeper than 40°). There are no warning signs.

Recommendations for action

• Navigate extremely steep slopes one person at a time.
• Be aware of the risk of falling.

Additional information

• Forecast for around 20% of the winter season.
• Around 5% of all avalanche fatalities occur when this danger level is in force.

This means danger level 2 (moderate danger)

Avalanches can be triggered by human activity on very steep slopes (steeper than 35°). There may be warning signs in isolated cases. Very large naturally triggered avalanches are not to be expected.

Recommendations for action

• Choose routes carefully.
• Navigate very steep slopes one person at a time.
• Take particular care when the structure of the snowpack is unfavourable (persistent weak layers).

Additional information

• Forecast for around 50% of the winter season.
• Around 30% of all avalanche fatalities occur when this danger level is in force.

Meaning of danger level 3 (considerable danger)

Situations where danger level 3 applies are the most critical for winter sports participants.

Avalanches can easily be triggered on steep slopes (steeper than 30°). Warning signs such as whumpfing sounds and cracks are typical but do not always occur. Naturally triggered avalanches and remote triggering are possible.

Recommendations for action

• It is essential to select the best possible route and implement measures to reduce risk.
• Avoid very steep slopes at the aspects and altitudes indicated in the avalanche bulletin.
• Inexperienced winter sports participants are advised to stay on open ski runs and trails.

Additional information

• Around 50% of all avalanche fatalities occur when this danger level is in force.
• Forecast for around 30% of the winter season.
• In some cases, sections of transport routes may be at risk (roads, ski slopes, hiking trails etc.). Observe closures.

Meaning of danger level 4 (high danger)

The avalanche situation is very critical. Avalanches can be easily triggered on many steep slopes. Warning signs and remote triggering are frequent, and very large avalanches are often likely. Transport routes (roads, ski slopes, hiking trails etc.) may be at risk.

Recommendations for action

• Be aware of the runout zones of very large avalanches.
• Inexperienced winter sports participants should stay on open ski runs and trails.
• Avoid steep slopes (steeper than 30°) altogether.
• Observe closures.

Additional information

• Around 10% of all avalanche fatalities occur when this danger level is in force.
• This danger level is forecast for a few days of the winter season.

Meaning of danger level 5 (very high danger)

The avalanche situation is exceptional. Numerous very large and extremely large naturally triggered avalanches are to be expected. These can reach and endanger roads and settlements in valleys.

Recommendations for action

• Do not undertake snow sports away from open ski runs and trails.
• Follow the instructions given by authorities.

Additional information

• Around 1% of all avalanche fatalities occur when this danger level is in force.
• This kind of exceptional avalanche situation is very rare.

Subdivisions

When there is a moderate or higher danger of dry-snow avalanches (starting from level 2), the SLF subdivides the points on the European avalanche danger scale. These subdivisions indicate whether the danger is estimated to be towards the bottom end (-), more or less in the middle (=) or towards the top end (+) of the forecast level.