Avalanche Forecast
Issued: Mar 21st, 2012 10:30AM
The alpine rating is Wind Slabs, Deep Persistent Slabs and Cornices.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Forecast snowfall amounts are uncertain on Thursday
Weather Forecast
A low pressure system pushing up from the south is expected to bring 10-15 cm new snow on Thursday. Ridgetop winds are expected to be strong southerly, diminishing to moderate westerly later on. Freezing level is expected to be around 1200 m. On Friday, unsettled air behind the system may give some lingering flurries, but winds should be light and sunny breaks should start to appear. Freezing level should increase to around 1400 m. Saturday should be generally dry, with significant periods of sunshine and light winds. Freezing level expected to climb to around 1800 m.
Avalanche Summary
A fatal avalanche incident occurred in this region on Wednesday. We will post more details when they become available. On Monday and Tuesday avalanche activity was isolated to the recent storm snow. On Sunday a large avalanche occurred in the Lumberton snowmobile area in the East Kootenays. A snowmobiler accidentally triggered a very large (Size 3+) avalanche that resulted in a close call.
Snowpack Summary
An additional 20-30cm of new snow on Tuesday with moderate to strong winds resulted in new wind slab formation in exposed leeward terrain. Several resistant shears have been noted in the storm snow. A sun crust on southern aspects and a spotty 2-6mm surface hoar on north and east aspects is down around 60-100cm. Below that, the more significant early February surface hoar is down 100-180cm. Avalanche activity has become more sporadic on this layer, but ongoing large events indicate it still has the ability to fail, despite how deeply it is buried. A melt-freeze crust, down 20-30cm, below 1800m provides some bridging to the layers below. Below the early February surface hoar layer, the snowpack is strong in most places. Cornices are very large and would act as a significant trigger for all the layers mentioned above if they drop.
Problems
Wind Slabs
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 22nd, 2012 9:00AM