Avalanche Forecast

Issued: Feb 8th, 2015 8:00AM

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

andrew jones, Parks Canada

Glacier.

Heavy precipitation and strong winds have created reactive storm slabs at higher elevations. New snow needs time to stabilize.

Summary

Weather Forecast

Only trace amounts of precipitation for today as an upper ridge of high pressure builds over the province. Expect moderate SE winds, freezing levels to 1700m and alpine high of -1. Warm and wet southwesterly flow resumes early Monday morning with the arrival of a pacific front. Expect 7cm of accumulation above 1800m and rain below.

Snowpack Summary

Intense rain in the last three days has left the upper snowpack moist or wet to around 2100m. Above 1900m there is 70-80cm of heavy storm snow. The Jan 30 surface hoar/crust layer, up to 2200m, is down 50-90cm and depth will depend on elevation. Jan 15 surface hoar layer is down 100-150cm and was reactive in artillery highway avalanche control.

Avalanche Summary

Observed several new large natural avalanches yesterday in the Highway Corridor. Most of the new slides began dry and ended moist, terminating farther than previous artillery triggered avalanches and in some cases gouging into existing debris.

Confidence

Problems

Storm Slabs

There is now about 1m of heavy storm snow above 1900m where temps have stayed below freezing. This storm slab is the triggering layer for recently observed large avalanches with far-reaching moist deposits.

The new snow will requires several days to settle and stabilize.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

2 - 3

Persistent Slabs

Recent intense precipitation and warm temperatures have the ability to reawaken deeper layers. Storm slabs avalanches may step down and propagate on these deep instabilities.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 4

Valid until: Feb 9th, 2015 8:00AM