Avalanche Forecast

Issued: Jan 16th, 2016 9:03AM

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

Avalanche Canada rbuhler, Avalanche Canada

Hazard continues to increase as the storm progresses. Building storm slabs overlie a touchy surface hoar layer and conservative terrain selection remains critical. In areas that get the most wind and new snow, the local hazard may be HIGH

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

A break in the storm is expected Saturday overnight before another storm pulse reaches the region on Sunday morning. Another 15-25cm of new snow is expected in the wettest parts of the region. Alpine winds should be moderate to strong from southwest and freezing levels are expected to reach around 1500m. Another 15-20cm is possible between Sunday evening and Monday morning before another break on Monday afternoon. Alpine winds are expected to be moderate from the southwest on Monday with freezing levels around 1200m. Another storm pulse is being forecast for Monday overnight or Tuesday morning.

Avalanche Summary

On Friday, a few natural storm slab avalanches size 2-2.5 were reported from a variety of aspects. These varied in thickness from 15-45cm and were releasing on the early-January surface hoar layer. On Thursday, natural avalanche activity up to size 2 was reported in the Pemberton area on north and east aspects. These were 30cm thick slabs releasing on a layer of surface hoar and facets. Explosives triggered a couple size 1.5 storm slabs in the Whistler area where the storm slab was only 10-20cm thick. Natural and human-triggered avalanches are expected to increase in size and reactivity as the storm progresses over the weekend.

Snowpack Summary

30-50cm of accumulating storm snow is now sitting above a widespread layer of surface hoar, facets, and/or sun crust on steep south aspects. 10-20 cm below this is a second buried weak layer of surface hoar and/or a crust. The mid and lower snowpack is generally strong, with the exception of shallower snowpack areas that may be more faceted. At lower treeline elevations recent rains have saturated the upper snowpack. At higher elevations moderate to strong southwest winds have recently loaded lee features at treeline and in the alpine.

Problems

Storm Slabs

An icon showing Storm Slabs
30-50cm of storm snow overlies a widespread layer of surface hoar. Strong SW winds will result in increased loading of leeward features.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain. >The new snow will require several days to settle and stabilize. >

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Valid until: Jan 17th, 2016 2:00PM