Avalanche Forecast

Issued: Jan 10th, 2014 8:42AM

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

Avalanche Canada jlammers, Avalanche Canada

Summary

Confidence

Good

Weather Forecast

Overnight and Saturday: Heavy snowfall occurring overnight and throughout Saturday / Moderate southwest wind (with extreme gusts) / Freezing level at 1100mSunday: Light snowfall / Moderate to extreme west winds / Freezing level at valley bottom rising to 1300mMonday: Light snowfall / Moderate to extreme southwest winds / Freezing level at 1300m

Avalanche Summary

On Thursday, numerous wind slab avalanches to size 1.5 were observed in alpine terrain. A size 2 deep persistent slab avalanche was reported on Blackcomb on Wednesday. This slide was accidentally triggered by a snow cat and failed on a weak facetted layer near the ground. Check out Waynn Flann's avalanche blog for photos and more information. This avalanche highlights the potential for large and deep avalanches in many areas on the South Coast. Heavy loading Friday night and Saturday will most likely trigger full depth avalanches in some places.

Snowpack Summary

Around 15-30 cm of new snow has fallen in the last few days and may overlie surface hoar in sheltered terrain. Ongoing moderate to strong southwest winds have formed touchy wind slabs in exposed lee terrain and cross-loaded features. The cold temperatures from early December have left weak faceted crystals that seem to be variably reactive. In higher elevation terrain where the snowpack was deeper, the facets likely co-exist with a crust in the mid pack. In lower elevation terrain or in shallow, rocky areas of the alpine, the facets are most likely more widespread and may exist down near the ground. Either way, the "wait 48 hours and you're good" Coastal mantra does not apply as these conditions are likely to persist for some time, and will probably become reactive with forecast snowfall.Early season riding hazards such as rocks, stumps and logs are lurking below the surface in many areas. In glaciated terrain open and poorly bridged crevasses are everywhere.

Problems

Storm Slabs

An icon showing Storm Slabs
Heavy snowfall and intense winds will create potent storm slabs at all elevations. Make conservative terrain choices.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Avoid areas with overhead hazard.>It is a good time to stay within the boundaries of a ski resort.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 5

Persistent Slabs

An icon showing Persistent Slabs
Saturday's storm loading will be the first big "shock" for weak sugar snow which formed during December's cold snap. Where this weakness exists, there is potential for very large and destructive avalanches.
Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 5

Valid until: Jan 11th, 2014 2:00PM