MISSION MTS. — Snow and cold weather are constantly changing and sometimes the changes come rapidly and dramatically over a short period of time. Avalanches involving people don’t happen by accident. There are three key factors that determine avalanche danger. 1) Terrain: the slope must be steep enough, generally 30 degrees or greater. 2) Snow pack: the snow must be unstable enough. 3) Weather: changing weather can quickly increase instability.

Nearly all avalanches that involve people are triggered by the victims themselves or member of their group. This is good news because it means that if we learn to recognize the warning signs, we can avoid avalanche danger.

Wind moves snow from windward to leeward slopes and can create the same kinds of unsafe conditions created by an intensive snow fall. Stay off leeward slopes during periods of strong winds. Watch for the leeward pockets.

Heavy trees provide protection from avalanches, but the trees must be spaced within three meters of one another. That’s close enough to make skiing annoying. Sparse trees do NOT provide any more protection than open slopes. Outdoor recreationists should examine travel plans and current weather conditions for changes. If you go to the backcountry to hike, snowshoe, ski, or snowmobile you should be aware of ways to reduce avalanche danger by following the recommended guidelines.

For more information on avalanche safety or updates on avalanche conditions visit glacieravalanche.org or Missoulaavalanche.org.