Avalanche Forecast
Issued: Feb 8th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Wind Slabs.
ahanna,
Avalanche Canada
Recent weather patterns have resulted in a high degree of variability within the region and a single hazard rating does not fit all areas. Be vigilant about verifying conditions in your area as you travel.
Hazard in the north of the region may be one step lower at all elevations.
Summary
Confidence
Weather Forecast
Monday night: Clear, light northwest ridgetop wind, alpine temperature -18.
Tuesday: Sunny, light northwest ridgetop wind, alpine high -15.
Wednesday: Mix of sun and cloud, light northwest ridgetop wind, alpine high -21.
Thursday: Mix of sun and cloud, light northeast ridgetop wind, alpine high -25.
Avalanche Summary
Recent snowfall focused in the Coquihalla zone has resulted in localized storm slab activity over the weekend. Natural and skier triggered avalanches averaging size 1-2 have been reported mostly on south aspects where they may be sitting over a slippery crust.
In the north of the region, recent avalanche activity has been limited to skier triggered wind slabs size 1-1.5.
Snowpack Summary
A stormy period from 4 to 8 February dropped approximately 60 cm of new snow in the Coquihalla, 40 cm near Allison Pass and 20 cm in the north of the region. This snow likely sits on a slippery crust on solar aspects, and possibly surface hoar elsewhere. Particularly in the Coquihalla, the new snow bonded poorly to these old surfaces and a number of avalanches were triggered on this layer. Looking forward, it is not clear whether the recent snow will bond, or whether this weak interface will remain a concern for several days. Given this uncertainty, a prudent approach would assume this is a suspect interface until we have more information.
An earlier persistent weak layer that formed in mid-January sits some way below the recent storm snow. This consists of facets at upper elevations, surface hoar in sheltered areas and a crust on south-facing slopes. Whumpfs were recently reported on this layer in the south of the region, indicating this layer might remain a concern there.
In the north, a melt-freeze crust from early December may be found 100 to 200 cm deep. Recent reports suggest that this layer is gaining strength and it has been unreactive in recent weeks.
Terrain and Travel
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Wind slabs may be poorly bonded to the underlying crust.
- Be careful as you transition into wind affected terrain.
- Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.
Problems
Storm Slabs
A storm slab problem exists in the south of the region, where 40-60 cm of new snow may sit on a crust on solar aspects and possibly surface hoar elsewhere. Looking forward, it is not clear whether the recent snow will bond, or whether this weak interface will remain a concern for several days. Given this uncertainty, a prudent approach would assume this is a suspect interface until we have more information.
Loose dry sluffing may also be observed in the new snow.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
A wind slab problem exists in the north of the region. Wind slabs may remain reactive especially where they sit over a crust on solar aspects, at ridgetops and roll-overs.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 9th, 2021 4:00PM
