Recent winds have created wind slabs on atypical aspects and at lower elevations than usual.
Recent strong northeast winds have heavily affected the upper snowpack. Firm, reactive wind slabs are most likely on southwest aspects but may exist on all aspects. These slabs likely sit atop a crust with weak, faceted snow above.
Widespread natural and human-triggered avalanche activity has been observed since Monday. Most avalanches have been wind slabs (size 1 to 2.5) occurring in alpine and treeline terrain on a variety of aspects.
Moving forward, we expect natural avalanche activity to decrease as winds ease and loose snow becomes less available for transport. However, human-triggered avalanches will remain possible.
Be sure to post your observations to the MIN if you get out!
Snow surfaces have been heavily wind-affected in the alpine and in exposed terrain at treeline and below. Windward slopes are scoured down to old crusts or sastrugi, while leeward slopes have been heavily loaded, forming firm wind slabs that may be sitting atop a crust with weak faceted snow or surface hoar.
In isolated, wind-sheltered terrain, 20 to 40 cm of low-density snow overlies a surface hoar layer, primarily at treeline and below.
A January crust with associated facets is buried roughly 60 to 120 cm below the surface. Below, the remainder of the snowpack is generally well settled and well bonded.
Wednesday Night
Clear skies. 30 km/h northeast ridgetop wind. Treeline temperature -16 °C.
Thursday
Mostly sunny. 20 km/h northwest ridgetop wind. Treeline temperature -12 °C.
Friday
Mostly cloudy. 2 to 4 cm of snow. 20 km/h south ridgetop wind. Treeline temperature -10 °C.
Saturday
Mostly cloudy. 1 to 2 cm of snow. 50 km/h southeast ridgetop wind. Treeline temperature -11 °C.
More details can be found in the Mountain Weather Forecast.
