Recent snow is sitting on a problematic weak layer, rider triggered avalanches are being reported on north and east aspects.
Retreat to mellower terrain if you see signs of instability.
A layer of surface hoar 30 to 55 cm deep buried at the end of January has been most reactive where a slab exists above it. Human triggered avalanches may become more widespread as any lower density snow also starts to settle into a slab.
Thursday: Reports of a few rider and remote triggered avalanches (size 1 to 2) on east aspects and north east aspects at all elevations.
Wednesday: West of Creston, explosive avalanche control produced several large slab avalanches (up to size 2.5) in southeast through southwest facing treeline terrain. Also, numerous small (up to size 1.5) loose avalanches were reported on steep slopes facing the sun.
30 to 55 cm of low density snow is settling over a layer of surface hoar buried at the end of January. In some parts of the region, alpine and treeline wind has formed deeper, denser deposits of snow in leeward terrain, and potentially scoured some windward ridgetops.
The buried surface hoar has been reported to be as large as 20 mm. On shaded slopes it's sitting on 10 to 20 cm of loose, sugary facets, but on sunny slopes it's sitting on a thin, hard crust.
This layer has been the culprit for many natural and human-triggered avalanches this week, and is not expected to break down and bond anytime soon.
The lower snowpack is strong and bonded.
Friday Night
Partly cloudy. 10 to 30 km/h west ridgetop wind. Treeline temperature -15 °C.
Saturday
Partly cloudy with up to 3 cm of snow. 10 to 40 km/h northwest ridgetop wind. Treeline temperature -9 °C.
Sunday
Sunny. 10 to 40 km/h northwest ridgetop wind. Treeline temperature -12 °C.
Monday
Sunny. 10 to 30 km/h northeast ridgetop wind. Treeline temperature -17 °C.
More details can be found in the Mountain Weather Forecast.
