Avalanche Forecast
Issued: Feb 20th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
MBender,
Avalanche Canada
There is uncertainty with how much snow is forecast to fall Saturday night and Sunday. Expect avalanche danger to rise through the day Sunday as snow accumulates and wind blows moderate to strong from the southwest.
Summary
Confidence
Weather Forecast
SATURDAY Night: Cloudy with flurries, accumulation 5-10 cm, moderate to strong southwest wind, alpine temperature -8 C.
SUNDAY: Cloudy with snowfall, accumulation 5-10 cm, moderate to strong southwest wind, alpine temperature -6 C.
MONDAY: Mainly cloudy with flurries, accumulation 2 to 5 cm, light west wind, alpine temperature -8 C.
TUESDAY: Mix of sun and cloud, light southwest wind, alpine temperature -13 C.
Avalanche Summary
Most recent reports show natural and skier triggered wind slab avalanches to size 1 and 1.5 in the alpine and treeline on Saturday as outlined in this MIN post here.
Snowpack Summary
Expect stormy conditions through the end of the weekend. The snow is forecast to fall with strong southerly wind, which should rapidly form new wind slabs in exposed terrain. As the snow accumulates widespread storm and wind slabs are expected to develop. The snow will overlie heavily wind affected and faceted surfaces in exposed terrain and perhaps a weak layer of surface hoar in sheltered areas, as found here.
The lower snowpack is strong around White Pass, but inland areas like the Wheaton Valley likely have a thinner and weaker structure.
Terrain and Travel
- Watch for avalanche hazard to increase throughout the day.
- Wind slabs are most reactive during their formation.
- Closely monitor how the new snow is bonding to the old surface.
- Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
Problems
Wind Slabs
New wind and storm slabs are expected to form as the wind blows and new snow falls. These slabs may not bond well to the surfaces beneath it, being composed of hard wind-affected snow, weak surface facets, and perhaps weak surface hoar in sheltered areas.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 22nd, 2021 4:00PM
