Avalanche Forecast

Issued: Feb 19th, 2012 9:11AM

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

jfloyer, Avalanche Canada

South Rockies.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Monday and Tuesday: flurries both days bringing minimal accumulation of new snow. Light to moderate NW winds increasing to strong NW on Tuesday. Freezing level around 800 m. Tuesday night into Wednesday: a slightly stronger band of moisture arrives bringing around 10 cm new snow, freezing levels rising to 1800 m and strong westerly winds.

Avalanche Summary

No recent avalanches have been reported from this region.

Snowpack Summary

Up to 20 cm of recent snow now sits on a variable weak layer comprising surface hoar (most prevalent in the west of the region), sugary facets on shady northerly aspects and sun crusts on solar aspects. These interfaces need watching as they receive more snow load and/or wind slab builds on top of these surfaces (see the forecaster blog for a good discussion on this). Below that, approximately 20 cm of near-surface facets can be found on shady slopes. While the mid-pack is quite strong in most locations, lingering concern remains for basal facets, particularly in shallower snowpack areas with steep, rocky start zones.

Problems

Wind Slabs

New snow and winds have developed wind slabs on lee and cross-loaded slopes.

Aspects: North, North East, East, South East, South.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

While still fairly shallow and therefore likely to produce mostly smaller avalanches, a weak layer currently buried around 20 cm needs to be closely watched, especially as the region receives more snow.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

Deep and destructive persistent slab avalanches are unlikely, but a large trigger may activate this weakness on a steep, rocky & unsupported area with a shallow snowpack.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

3 - 6

Valid until: Feb 20th, 2012 9:00AM