Avalanche Forecast

Issued: Feb 16th, 2012 9:00AM

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

istorm, Avalanche Canada

South Rockies.

Summary

Confidence

Good

Weather Forecast

Thursdays weak storm with light precipitation should clear out with Friday having a mix of sun and cloud. The sun will warm things up on southerly slopes with freezing level around 1300 m. Then next storm is expected to arrive overnight Friday with Saturday being a snow day. I expect around 10 cm. The wind veers to the NW Sunday with a mix of sun & cloudy, localized convective snow showers.

Avalanche Summary

Small loose snow or thin slabs are reported from steep terrain Tuesday & Wednesday. Only surface snow involved. Deep persistent slab avalanches remain possible in isolated terrain features; i.e. heavy triggers in shallow rocky snowpack areas on unsupported slopes. Check out the Avalanche Image Gallery under the Library tab for some photos of last weekends deep persistent slab avalanche cycle.

Snowpack Summary

Sunshine on Wednesday formed a crust on many southerly (SE, S, and around to the west) facing slopes. Shady slopes remain dry. Around 20 cm of recent snow which fell over the past few days is sitting on the widespread major surface hoar layer in many locations, sugary facets on shady N'ly and sun crusts on solar aspects. These interfaces need watching as they receive more snow load and/or the slab settles. Below that approximately 20cm of near-surface facets can be found on shady slopes while a sun crust can be found on southerly aspects. While the midpack is quite strong in most locations, basal facets remain a concern on shady alpine slopes that did not avalanche in the last cycle.

Problems

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

Wind Slabs

Slabs likely aren't very big (thick) yet, however, they rest on either a sugary snow layer or a smooth sun crust. In other words, they could be wider or run farther than you might otherwise expect.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Cornices

Cornices are large, unsupported and may be a trigger for a large avalanche on the slope below.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Feb 17th, 2012 9:00AM