Avalanche Forecast
Issued: Mar 24th, 2013 9:12AM
The alpine rating is Wind Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair
Weather Forecast
Monday: Light to moderate snowfall â around 10 cm. The freezing level is around 1000 m and winds are moderate to strong from the south-southeast. Tuesday: Clearing through the day. The freezing level is around 1000-1200 m. Winds ease to light from the southwest. Wednesday: A mix of sun and cloud. Temperatures warm slightly with the daytime freezing level jumping to around 1500 m.
Avalanche Summary
Naturally-triggered wind slabs and loose moist avalanches have been observed over the last couple of days. Ice fall also triggered size 2.5-3 avalanches near Bear Pass and other areas. On Saturday there was a report of a size 2 avalanche triggered from a distance on a snowmobile. This slide likely failed on the March 9 surface hoar. Many skier-triggered and skier-remote avalanches of size 1-2.5 were reported last week, with the bulk of events failing on the March 9th surface hoar layer down around 50 cm. Numerous other skier-remote (from up to 800 m away) avalanches of size 2-2.5 also failed just to the NE of the forecast region, on the same layer. A very large (size 3.5) avalanche was triggered in Cherry Bowl in the Shames backcountry on Sunday. Click here for a full report.
Snowpack Summary
Recent new snow overlies surface hoar, crusts and old wind slabs. New wind slabs have formed lee to SW to NW winds. The surface hoar (buried March 9th; now down about 40-60 cm) has been found at all elevations, but its reactivity is becoming more variable. Whumfing and remote-triggering of avalanches last week indicated the volatility of the layer. A slow improvement is occurring, but confidence is not soaring amongst professionals. Triggering this layer is becoming a low probability but high consequence problem. Check out the Forecaster's Blog for tips on how to deal with this type of problem. A second surface hoar layer, buried on March 18, is also problematic in some areas. The mid snowpack is generally well settled and strong. Cornices are large and untrustworthy, especially when the sun is out.
Problems
Wind Slabs
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 25th, 2013 2:00PM