Avalanche Forecast
Issued: Mar 11th, 2013 9:02AM
The alpine rating is Storm Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain for the entire period
Weather Forecast
Synopsis: A steady southwest flow will drive a series of disturbances onto the south coast this week. There is some uncertainty regarding the timing of each pulse of heavier precipitation, but itâs fairly certain to be a wet and mild week. Overnight and Tuesday: Moderate precipitation â 10-20 cm. The freezing level will rise to around 1500 m by Tuesday afternoon. Winds are strong from the south-southwest. Wednesday: Moderate to locally heavy precipitation â 15-20 cm. The freezing level climbs to 1800 m. Winds remain strong from the south-southwest. Â Thursday: Moderate precipitation continues. The freezing level starts near 1600 m but could drop later in the day or by Friday morning. Â
Avalanche Summary
Thin wind slabs to size 1.5 were skier triggered on steep north facing slopes on Saturday and Sunday. They were reported to have released on surface hoar buried on March 9th. There was a report of a size 2 skier triggered slab avalanche on a steep southwest apsect in the Steep Creek area (Duffey Lake). This incident happened a few days ago, but highlights the lingering potential for triggering large slab avalanches.
Snowpack Summary
A dusting of new snow overlies a variety of old surfaces which include: a crust at lower elevations and on solar aspects, faceted powder on shaded slopes, and surface hoar. The surface hoar, which was reported from the north of the region, has already been reported to be reactive where it was buried by wind slabs formed by strong southwest winds on Saturday.Between 50 and 80cm below the surface is a layer surface hoar which was buried on February 20th. Triggering this layer has become difficult, but heavy snow or rain this week could be enough new load to awaken this layer in specific areas. Below this the snowpack is generally well settled and strong.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 12th, 2013 2:00PM