Avalanche Forecast
Issued: Feb 28th, 2021 9:06AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Wind Slabs and Persistent Slabs.
Kate Ryan,
Use caution transitioning into wind affected terrain and watch for signs of slab development, such as shooting cracks.
Summary
Weather Forecast
This past week we've been receiving significantly more snow than forecast.
Today: Mainly cloudy with isolated flurries accumulating to 2cm. Freezing level 1300m. Winds SW-25km/h
Tonight: Mainly cloudy with isolated flurries. Freezing level 1000m. Winds SW-30km/h.
Monday: Mainly cloudy. Freezing level 1300. Winds SW-35km/h gusting to 80km/h.
Snowpack Summary
More snow has fallen on the west end of the park than east. Since Wednesday, up to 70cm has been redistributed by sustained moderate S'ly wind. The Feb 14 drought interface is down ~1m in sheltered areas; this interface exists as a wind crust in exposed areas near the Pass, and buried windslabs, facets, or a thin suncrust as you move East or West.
Avalanche Summary
Yesterday, a solar induced natural avalanche cycle occurred from steep south aspects in the alpine to size 2.5, as well as a smaller wind-induced cycle from steep northerly aspects to size 2.0. Several storm slabs from size 1.5-3.0 were triggered by Fridays convective snowfall, most notably 2 size 3.0s from Manix and Gunners (S aspects).
Confidence
Problems
Storm Slabs
Up to 70 cm of new snow this week has formed fresh storm slabs. These will be more reactive in exposed areas where they have been stiffened by the wind and overlay a crust.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
- Watch for signs of slab formation, such as whumpfing and shooting cracks.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
The central and eastern areas of Glacier have received more wind than the west. With lots of new snow available for transport, expect fresh windslab development in lee features and increased cornice growth.
- Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.
- Use caution in lee areas in the alpine and treeline. Recent storm snow has formed wind slabs.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
The 80+ cm of snow we received Monday sits on the February 14th weak layer.
This problem may persist longer in areas where the facets are well preserved, or on steep solar aspects where these is a thin suncrust at this interface.
- Be wary of large open slopes that did not previously avalanche.
- Dig down to find and test weak layers before committing to a line.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 1st, 2021 8:00AM
