Avalanche Warning Levels

 

Danger Level

Icons

Snowpack Stability

Avalanche Triggering Probability

1. Low

Avalanche low risk

The snowpack is well bonded and stable in general

Triggering is generally possible only from high additional loads** in isolated areas of very steep, extreme terrain. Only sluffs and small-sized natural avalanches are possible

2. Moderate

Avalanche low risk

The snowpack is only moderately well bonded on some steep slopes*, otherwise well bonded in general

Triggering is possible primarily from high additional loads**, particularly on the indicated steep slopes*. Large-sized natural avalanches are unlikely

3. Considerable

Avalanche low risk

The snowpack is moderately to poorly bonded on many steep slopes*

Triggering is possible, even from low additional loads** particularly on the indicated steep slopes*. In some cases medium-sized, in isolated cases large-sized natural avalanches are possible

4. High

Avalanche low risk

The snowpack is poorly bonded on most steeps slopes

Triggering is likely even from low additional loads** on many steep slopes. In some cases, numerous medium-sized and often large-sized natural avalanches can be expected

5. Very High

Avalanche low risk

The snowpack is poorly bonded and largely unstable in general

Numerous large-sized and often very large-sized natural avalanches can be expected, even in moderately steep terrain

 

* Avalanche bulletins describe in great detail avalanche-prone locations (type of terrain, altitude, slope aspect, proximity to ridge, smoothness of underlying ground surface..)
    • Moderately steep terrain: slopes shallower than 30 degrees
    • Steep slope: slopes steeper than 30 degrees
    • Very steep terrain: more than 40 degrees

 

** Additional loads:
Low:
    • Individual skier or snowboarder, riding softly and not falling
    • Group keeping distances with spacing over 10m

High:
    • 2 or more skiers, snowboarders, etc. not keeping distances
    • Single climber/hiker
    • Snowmachine
    • Explosives

 

13 January 2016 Author Paul Quigley