Avalanche Forecast

Issued: Jan 13th, 2014 8:43AM

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

Avalanche Canada bcorrigan, Avalanche Canada

Summary

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

Overnight: No precipitation in the forecast, winds strong from the W, freezing lowering to valley bottom.Tuesday: No precipitation in the forecast, moderate to strong winds from the west, freezing levels may rise to 1200m in parts of the forecast area.Wednesday: No precipitation in the forecast, winds from the NW, freezing levels rise as high at 1900m in some parts of the forecast area.Thursday: No precipitation, light wind at ridge tops, freezing level climbing to 2300 m in parts of the forecast region.

Avalanche Summary

A natural avalanche cycle has been reported throughout the forecast area with avalanches running full path up to size 3. Buried persistent weaknesses may now become reactive with heavy loading from snow and wind. Until the snow pack adjusts to the new load, heightened avalanche awareness and caution is needed to travel safely in avalanche terrain.

Snowpack Summary

Parts of the forecast area have received over 70cm of storm snow, which now overlies a variety of old surfaces ranging from wind slabs, to a soft layer of facetted snow and/or surface hoar from earlier in January, now buried in the snowpack between 60 and 85cm.100cm or more below the surface there is a thin melt freeze crust below 2100m elevation, as well as other buried weak layers (surface hoar, facetted snow, and/or a crust) that continue to be reactive in snowpack tests. There are two deeper layers of note. The late-November persistent weak layer is a sun crust on steep south facing slopes and surface hoar in sheltered areas and now may be 200cm below the surface. The October deep persistent weak layer consists of a layer of facets sitting on a crust at the base of the snowpack. This layer is predominantly found on northerly aspects at tree line and in the alpine. The depth of both these layers makes directly triggering an avalanche on them unlikely (maybe a heavy load on a thin spot in steep terrain), an avalanche stepping down to this layer might dramatically increase the size of the avalanche.

Problems

Storm Slabs

An icon showing Storm Slabs
Operators have reported that the Jan 8th surface hoar,(now 60 - 80 cm's below the surface), is still reactive in snow pack tests. Avoid riding large features and unsupported slopes.
Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>Avoid all avalanche terrain.>The new snow will require several days to settle and stabilize.>Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 5

Persistent Slabs

An icon showing Persistent Slabs
The presence of persistent weak layers increases the likelihood of larger avalanches that could release to a depth of a metre or even more.
Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Jan 14th, 2014 2:00PM