Avalanche Forecast

Issued: Feb 29th, 2012 9:29AM

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

Avalanche Canada swerner, Avalanche Canada

The snowpack is tricky to predict at the moment. Backcountry travel requires local knowledge, extensive experience and training. Please read the new Forecaster's Blog Post.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Thursday: Fairly benign, cloudy in the morning with scattered flurries, skies clearing and sunshine in the afternoon. Ridgetop winds light from the North. Treeline temperatures near -8. Friday: A series of systems will arrive, with a decent moisture feed from the SW. The morning looks to be fairly dry, and cold. Light snow amounts will start up in the afternoon. Ridgetop winds moderate-strong from the WSW. Treeline temperatures near -6, as freezing levels may rise to 900m. Saturday: Continued snow, light in the am becoming moderate in the afternoon. Ridgtop winds steady moderate from the SW. Freezing levels could rise to 1000m later in the day.

Avalanche Summary

Reports of natural activity have started to taper off, but rider triggers are likely and still occurring. Numerous rider triggered avalanches up to size 2 have been reported in the Northern half of the region, where the Southern half has been quiet (maybe less people are out and about?). Rider triggered slides are on most aspects below 2000 m. The mid February interface is to blame for avalanche activity near treeline and below. Backcountry travel requires local knowledge, extensive experience and training. The obvious clues that show snowpack instability may not be there. You need to dig deep, do your detective work and make good decisions. Don't let the sunny skies, and other tracks fool you, and/ or lead you into a situation you won't be able to deal with. Visit the link below to check out the recent incidents in your area: http://www.avalanche.ca/cac/library/incident-report-database/view

Snowpack Summary

Pockets of wind slab exist on multiple aspects and elevations from constant changing wind. Dribs and drabs of new snow fell over the week, while the main bulk of the storm snow is from last weekend. The Duffy saw up to 25 cm, and the Coquihalla saw near 40 cm. In both areas, the mid February interface is down approximately 60 cm below the surface. At the moment, this is the interface of concern which has created tricky snowpack conditions. This includes crusts at lower elevations, and buried surface hoar in protected areas. This layer has been reactive to natural and rider triggers, especially around treeline elevations producing large avalanches, and catching people by surprise. Below this the lower snowpack is well bonded and strong. Solar radiation may be a factor on Thursday afternoon, avoid sunny slopes if you see obvious signs of snowpack deterioration (natural avalanche activity, snowballing, moist and/or surface snow).

Problems

Wind Slabs

An icon showing Wind Slabs
Changing winds have created more widespread wind slabs. Cracking, whumphing and/or hollow drum like sounds beneath you are all indicators.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
Storm slabs linger and remain reactive where they exist in combination with buried surface hoar; especially in sheltered treeline locations. Avalanches sliding on this layer may be large and destructive.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Valid until: Mar 1st, 2012 8:00AM