Avalanche Forecast

Issued: Jan 16th, 2016 9:26AM

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

New snow and wind continue to add to the size and reactivity of recently formed storm slabs. Tricky conditions are expected to continue and conservative terrain selection remain critical.

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 10-20cm 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 5-15cm 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, dry sluffing was reported from steep north facing slopes in the alpine and isolated loose wet sluffing was reported from sun exposed slopes below treeline. On Thursday, no new slab avalanches were reported but one natural cornice release was observed. This was a size 2 cornice release from a north aspect at 2300m elevation. The cornice entrained loose snow but did not trigger a slab. Natural and human-triggered avalanches are expected to increase in size and reactivity as the storm progresses over the weekend and into early next week.

Snowpack Summary

The new storm snow is burying the recently formed mid-January surface hoar layer. Down 20-40cm are the early-January interfaces which are separated by around 15cm of snow and both consist of a sun crust on steep solar aspects and a layer of surface hoar on sheltered and shady slopes. Moderate to strong southeast through southwest winds have been loading lee features at treeline and in the alpine. The mid and lower snowpack is generally strong, with the exception of shallow snowpack areas that may be more faceted. At lower elevations below treeline recent rain may have saturated the upper snowpack.

Problems

Storm Slabs

An icon showing Storm Slabs
Continued snowfall is building storm slabs which are typically 20-30cm thick and overlie a widespread layer of surface hoar. Strong SW winds will result in increased loading of leeward features.
The new snow will requires several days to settle and stabilize. >Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved. >Avoid freshly wind loaded features. >

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

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