Avalanche Forecast

Issued: Feb 12th, 2014 8:40AM

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

Avalanche Canada bcorrigan, Avalanche Canada

Snowfall amounts may vary widely across the forecast region.  Higher than forecast snow amounts could dramatically increase the hazard. forecast.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

A series of Pacific low pressure systems will bring snow to the forecast area for the next  5 to 7 days. Forecast models vary on amounts and some parts of the area may see larger amounts of precipitation.Wednesday night:  Freezing Level at valley bottom  Trace of precipitation as the front moves to the east, winds moderate to strong from the south west at ridge top.Thursday:  Freezing level: 1300m;    Another wave of moisture through the interior on Thursday with light to locally moderate amounts of precipitation. A minor clearing on Thursday night before the next system. Winds from the south west, moderate to strong at ridge top.Friday:        Freezing level: 1100m;   Yet another wave will bring more snow to the region, with continued moderate to strong winds at ridge top.Saturday:  Freezing level around 900m   A bit of a break in the weather on Saturday.  Flurries with a trace of precipitation, light winds at ridge top.

Avalanche Summary

Reports of numerous size 1 to 1.5 skier controlled and natural avalanches up to size 2 in the past 24 hrs. We expect the number of reported avalanches to increase with the snow loading and strong upper elevation winds.

Snowpack Summary

Some parts of the Purcells have received up to 40+cm of storm snow in the past 48 hrs on a variety of weak surfaces(surface hoar, facets, sun crust) These weak layers will be problematic for the near future and it will take time for the new snow to bond with the old surfaces. Significant weak layers of large surface hoar and facetted snow are now buried 10 to 30 cm below the new snow surface. These weak layers are expected to remain a problem for the foreseeable future. The rest of the snowpack is generally well consolidated. Forecast strong winds at ridge tops will redistribute the new snow and form wind slabs on lee slopes. A facet/crust weakness near the bottom of the snowpack has gone dormant for the most part. The depth of this layer makes triggering an avalanche unlikely but the consequences would be very serious.

Problems

Storm Slabs

An icon showing Storm Slabs
Snow fall amounts vary across the Purcells, but the new snow is generally falling on old weak surfaces.  Strong winds are building wind slabs at tree line and above.  Special attention is needed to travel/ride safely in the back country right now.
Use caution in lee areas in the alpine and at tree line. Recent wind loading has created wind slabs.>Be careful with wind loaded pockets. Be aware of wide variation in snowpack depth>Be aware of thin areas that may propogate to deeper instabilites.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Feb 13th, 2014 2:00PM