Dangerous avalanche conditions exist. A strong winter storm this week deposited three feet of snow and five inches of moisture in the mountains. Strong winds during the snowfall further aided in the development of wind slabs at all elevations. Yesterday these slabs were very sensitive to human triggers and were releasing naturally. No one was injured when one of these natural events hit a truck on the highway near Astoria Hot Springs in the Snake River Canyon. Although not expected to release naturally today, these slabs will continue to be sensitive to backcountry skiers and riders. Conservative decision making is essential.
Strong southwest to west winds during recent heavy snowfall have formed dense surface slabs on leeward aspects. These slabs lie upon faceted snow formed during last weeks cold period. These slabs will be most sensitive at the higher elevations where slab depths could reach four feet.
A slight chance exists for larger loads to initiate very large and destructive deep slab avalanches that could involve the full depth of the snowpack.
High pressure will dominate on Friday. Below zero temperatures are expected in the morning with slight inversion conditions. Highs are to be in the teens. Winds will be light. The avalanche hazard will be Considerable. The possibility for humans to easily trigger soft to hard surface slabs will continue. These slabs could have depths ranging from six inches to several feet and could occur at all elevations and most aspects. Although less likely, deep slab avalanches could also be triggered in high terrain on northerly aspects by larger loads such as snow machines or by the initiation of a surface slab.
