Avalanche Forecast

Issued: Feb 3rd, 2021 4:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Persistent Slabs.

Avalanche Canada kdevine, Avalanche Canada

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Fresh snow and wind may build increasingly reactive storm slabs throughout the day.

Some areas may see enhanced snowfall amounts of 15-20 cm. Pay attention to changing conditions and be prepared to dial back your terrain choices if you see more than 15 cm of new snow.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

WEDNESDAY NIGHT - Mainly cloudy with a few flurries / moderate to strong west wind / alpine low temperature near -10 

THURSDAY - Flurries, 5-10 cm, with the potential for some isolated enhancement bringing 15-20 cm to some areas / strong northwest wind / alpine high temperature near -7

FRIDAY - Mainly cloudy with a few flurries / moderate northwest wind / alpine high temperature near -6 / freezing level 1300 m 

SATURDAY - Mainly cloudy with flurries, 5 cm / moderate west wind / alpine high temperature near -7

Avalanche Summary

Human triggered avalanches will remain likely on Wednesday, especially in wind loaded areas at higher elevations. 

There were a few reports of size 1-1.5 natural and human triggered avalanches in the region on Tuesday.

There were several reports of size 1-2.5 natural, human and explosives triggered avalanches in the region on Monday. It is suspected that some of these failed on the recently buried persistent weak layer.

There were several reports of size 1-1.5 natural and human triggered avalanches in the region on Sunday.

Snowpack Summary

5-10 cm of snow is expected throughout the day on Thursday, though some areas may see isolated enhanced snowfall amounts of 15-20 cm. Moderate to strong northwest winds will likely form reactive slabs in the alpine and open treeline areas.

30-60 cm of recent fresh snow sits on a persistent weak layer that consists of facets at upper elevations, surface hoar in sheltered areas, a melt-freeze crust below 1600 m, and a sun crust on south-facing slopes. 

In the south, the underlying snowpack is well consolidated. 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

  • Watch for changing conditions today, storm slabs may become increasingly reactive.
  • Avoid freshly wind loaded terrain features.
  • Be aware of highly variable recent wind loading patterns.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.

Problems

Storm Slabs

An icon showing Storm Slabs

Storm slabs will likely continue to be reactive, especially in wind loaded areas, and in any places that see more than 15 cm of new snow on Thursday.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

30-60 cm sits on a buried weak layer that consists of facets, surface hoar, or a crust, depending on location. Avalanches on this layer may propagate widely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Feb 4th, 2021 4:00PM

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