Very dangerous avalanche conditions.
High is the second highest level on the avalanche danger scale. During periods of High danger, avalanche conditions are very dangerous and travel in avalanche terrain is not recommended. Natural avalanches are likely and human-triggered avalanches are very likely. Large avalanches are expected in many areas or very large avalanches in specific areas.
Under High danger, a natural avalanche cycle is underway, or conditions are very sensitive to human triggers on either end of a cycle. Avalanche terrain should be avoided. Use extra caution when traveling in simple terrain and stick to very mellow slopes or dense trees that are free of overhead hazards. Remember that you don’t have to be on a steep slope to be struck by an avalanche that starts from above you. Small terrain features that may seem benign, such as roadcuts or creekbeds, could be dangerous.