Avalanche Forecast

Issued: Feb 2nd, 2015 8:34AM

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

Avalanche Canada triley, Avalanche Canada

A new storm slab is developing. Watch for continued loading from the forecast new snow and wind this week.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Flurries and periods of light snow overnight are expect to accumulate 5-10 cm by Tuesday morning combined with moderate Northwest winds and alpine temperatures around -10. Tuesday is forecast to be drier with only periods of flurries along the area of colder arctic air to the Northeast. Light precipitation is expected to continue on Wednesday with light to moderate Southwest winds ahead of the next storm. The storm should start on Thursday, and at this time it looks like we may get 15-20 cm in the first pulse of moisture and then continued precipitation into the weekend.

Avalanche Summary

No new avalanches reported on Sunday. I expect that the new storm snow may have been easy to trigger where it was overlying a crust and/or surface hoar that was buried on January 30th. The new storm snow is likely to settle into a soft slab over the next few days.

Snowpack Summary

Up to 35cm of new snow fell over the weekend. This new snow sits on a variety of old surfaces. A crust can be found below about 1900m in the north of the region and below 2200m in the south of the region. At higher elevations the new snow covers old wind slabs formed by moderate southwest winds. Several persistent week layers can be found deeper in the snowpack that may be capped by the overlying crust at lower elevations. The mid-January surface hoar is buried between 40 and 80cm down and remains a concern at treeline and above. The mid-December surface hoar layer is now 80 to 140cm below the surface and appears to be slowly gaining strength.

Problems

Storm Slabs

An icon showing Storm Slabs
Recent storm snow may have settled into a soft slab above the old surface crust and/or a new layer of surface hoar. Fracture propagation may increase as the new storm slab settles.
Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Be cautious of sluffing in steep terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
The mid-January weak layer may continue to be triggered in some areas where the buried crust and surface hoar combination still exists. This may be isolated to terrain that remained coll during the warm up last week.
Carefully evaluate and use caution around thin snowpack areas.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Feb 3rd, 2015 2:00PM