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RegisterFeb 9th, 2019–Feb 10th, 2019
Stevens Pass.
The storm may have tapered off, the but avalanche danger has not. Easterly winds through the pass formed slabs in unusual locations on Saturday. The wind drifted snow may be resting on a layer of weak, sugary facets over a crust, a recipe for slab avalanches. Stay off of steep slopes in wind loaded areas.
A little less than a foot of low density fluff fell overnight Friday, then easterly winds cranked-even below treeline. Avalanche professionals were able to trigger small wind slabs very easily in the morning, and these became more reactive towards the afternoon as the wind continued. Prior to the storm, the very cold temperatures turned a layer of low density snow into facets. These facets rest over a mostly supportable crust, and are fairly widespread above 5,000ft. An observer reported a significant collapse on a South aspect at 5,100ft on Saturday. This was in a location that was wind loaded with a slab about 16” thick. They headed down to change their underwear, and reported that the ski quality was variable to poor after the winds did their thing. As the storm snow becomes more cohesive, conditions may actually become more dangerous with time as the slab may begin to communicate a fracture across the terrain more easily on Sunday than on Saturday. This is a fairly unusual situation for the Cascades, and one to be taken very seriously as the cold temperatures and snowfall continues into the week ahead.
Facets are angular snow grains that bond poorly to other grains around it. Once formed, buried, and preserved, they tend to persist in the snowpack. They are often the culprit of delayed action avalanches that result in avalanche accidents.
Coming Soon.