Avalanche Forecast

Issued: Nov 26th, 2015 8:39AM

The alpine rating is below threshold, the treeline rating is below threshold, and the below treeline rating is below threshold. Known problems include Wind Slabs and Deep Persistent Slabs.

bcorrigan, Avalanche Canada

Purcells.

Rising alpine temperatures up to +5c are in the forecast for the next few days. Use care venturing into big terrain at treeline and above. Consider sharing your observations through the Mountain Information Network MIN

Summary

Weather Forecast

An arctic high persists in the forecast region with no precipitation in the forecast for the next 4 days. An above freezing layer (AFL) is forecast to move into the region Friday with temperatures up to +5c between 1500 and 3000m. Skies should be sunny and clear at upper elevations with valley temperatures below freezing and the possibility of valley fog in the mornings dissipating in the afternoon.

Avalanche Summary

Reports from operators speak of low density size 1's failing on the Nov.23rd surface hoar layer now buried by 10 to 20cm of storm snow

Snowpack Summary

Monday's storm snow fell on a variety of old surfaces including crust, surface hoar and old settled snow. Arctic air moving into the region has resulted in northerly winds forming small wind slabs on south facing features near ridge top and t tree line. Warm temps and strong solar input formed a crust on south facing features which can be found underneath Monday's storm snow. There are at least three surface hoar layers in the snowpack buried on: Nov. 5th, Nov. 11th and Nov. 23rd. The first two have been largely unreactive. Facets may exist just above the ground on shaded slopes in the alpine. Rapid rising temperatures forecast for the next few days may change the snowpack dramatically.

Problems

Wind Slabs

Strong winds from the north in the past few days have redistributed storm snow over surface hoar on shaded aspects and may be hiding suncrust on solar aspects.

Be cautious as you transition out of wind sheltered terrain.>Avoid freshly wind loaded features.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

Snow from early in the season has become facetted and weak at the base of the snowpack, mostly on northerly aspects

Now is a good time to dig a snow profile (or two) and figure out how the snowpack changes with aspect and elevation.>Be aware of thin areas that may propogate to deeper instabilites.>

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

2 - 5

Valid until: Nov 27th, 2015 2:00PM