Avalanche Forecast

Issued: Mar 2nd, 2013 9:45AM

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

pgoddard, Avalanche Canada

Sea To Sky.

Watch out for slopes being warmed by direct sun. This may locally raise the avalanche danger.

Summary

Confidence

Fair

Weather Forecast

Sunday: Clearing up and becoming sunny. Light winds. Freezing level around 900 m.Monday: No snow. Sunny breaks. Light winds. Freezing level around 1200 m.Tuesday: Light snow. Light S winds. Freezing level around 1000 m.

Avalanche Summary

A widespread large natural avalanche cycle is suspected to have occurred on Friday, but poor weather limited observations, especially of alpine terrain. Numerous size 1-2 slabs were triggered naturally and by skiers directly, remotely, and sympathetically at and below treeline. These failed on either storm slab weaknesses or buried persistent weak layers.

Snowpack Summary

Low density snow had high density snow or rain (depending on elevation) piled on top of it at rapid loading rates during the recent storm. Storm totals are around 1m of snow (over 100 mm of rain below about 1500 m). Storm slabs were very touchy on Friday. Strong southerly winds have shifted snow into wind slabs and hard wind-pressed surfaces in exposed terrain. A weakness of surface hoar and/or a crust exists within the upper snowpack, which has been reactive over the last week, creating very large avalanches. Cooling is expected to help stabilize the snowpack quickly at low elevations, and more slowly at upper elevations. Direct sunshine may trigger some further shedding of storm snow on Sunday/Monday. The lower snowpack is well settled.

Problems

Storm Slabs

Storm snow will take some time to stabilize. Sunshine could weaken new snow and cause some more avalanche activity.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Start with low angled slopes and test the bonding of recent storm snow before considering steeper objectives.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Persistent Slabs

Persistent weaknesses have been touchy recently and can increase the size and consequence of avalanches.

Be wary of paths that have not avalanched recently.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 7

Valid until: Mar 3rd, 2013 2:00PM