Avalanche Forecast
Issued: Jan 5th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
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Avalanche Canada
Navigate around wind loaded slopes and keep in mind the potential for surprisingly large avalanches due to isolated weak layers.
Summary
Confidence
Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.
Weather Forecast
A weak front crosses the region on Wednesday then clearing weather into the weekend.
TUESDAY NIGHT: Cloudy, strong southwest wind, temperatures around -5 C.
WEDNESDAY: Scattered flurries throughout the day with 5-10 cm of snow, moderate southwest wind, temperatures around -3 C.
THURSDAY: Cloudy in the morning then clearing in the afternoon, light north wind, temperatures around -5 C.
FRIDAY: Sunny, light wind, temperatures around -5 C.
Avalanche Summary
A few small (size 1-1.5) storm and wind slab avalanches were reported on Monday and Tuesday. A natural cycle of larger (size 2-3) storm slab avalanches occurred over the weekend during a more intense storm. There was also persistent slab avalanche on Sunday that was remotely triggered in a north facing gully around 1350 m (see the photo here). The avalanche failed on a 50 cm deep surface hoar layer, and illustrates how the current persistent slab problem is lingering in isolated areas.
Snowpack Summary
Moderate snowfalls and strong southwest wind over the past few days has likely left hard surfaces and wind slabs in exposed terrain. Roughly 30-40 cm of recent snow is settling above a crust that extends up to 1900 m. The main feature we are monitoring in the snowpack is a layer of feathery surface hoar and/or faceted grains over a hard melt-freeze crust found 50 to 100 cm deep. Reports suggest this layer is strong and bonded in most terrain, but remains suspect in the isolated areas where it is preserved. Unfortunately we do not have a clear picture of where this isolated areas exist.
Terrain and Travel
- Be carefull around freshly wind loaded features.
- Choose slopes that are well supported and have limited consequence.
- Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
Problems
Wind Slabs
Strong southwest wind and a series of moderate snowfalls over the past few days has likely left reactive slabs in steep leeward terrain.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
The snowpack across the region has some isolated areas where persistent weak layers linger, including surface hoar and/or facets above a crust 50 to 100 cm below the surface. This is a difficult problem to manage because it does not seem to exist in most terrain, but in the isolated places where it does exist it can produce large destructive avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 6th, 2021 4:00PM
