Avalanche Danger Scale
In the US and Canada, the following avalanche danger scale is used:
| Risk | Degree of Danger | Distribution of Danger |
Recommended Action in Back Country |
|---|---|---|---|
| Low (green) |
Natural avalanches very unlikely. Human triggered avalanches unlikely. |
Generally stable snow. Isolated areas of instability. |
Travel is generally safe. Normal caution advised. |
| Moderate (yellow) |
Natural avalanches unlikely. Human triggered avalanches possible. |
Unstable slabs possible on steep terrain. | Use caution in steeper terrain |
| Considerable (orange) |
Natural avalanches possible. Human triggered avalanches probable. |
Unstable slabs probable on steep terrain. | Be increasingly cautious in steeper terrain. |
| High (red) |
Natural and human triggered avalanches likely. | Unstable slabs likely on a variety of aspects and slope angles. | Travel in avalanche terrain is not recommended. Safest travel on windward ridges of lower angle slopes without steeper terrain above. |
| Extreme (red/black border) |
Widespread natural or human triggered avalanches certain. Large destructive avalanches possible. |
Extremely unstable slabs certain on most aspects and slope angles. | Travel in avalanche terrain should be avoided. Travel should be confined to low angle terrain well away from avalanche path run-outs. |
