Avalanche Forecast

Issued: Nov 29th, 2014 8:04AM

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

triley, Avalanche Canada

Sea To Sky.

Outflow winds are transporting snow in the alpine into pockets of windslab. Cold and clear weather is forecast to continue.

Summary

Confidence

Poor - Due to the number and quality of field observations

Weather Forecast

The ridge of high pressure is forecast to remain over the province giving cold and clear conditions for Sunday. Some cloud may move into the region on Sunday night as a low pressure system slides down the coast from Alaska. Clear and cold returning for Monday and Tuesday, but cold Northerly outflow winds should end on Sunday.

Avalanche Summary

No new avalanches reported.

Snowpack Summary

Strong Northeast outflow winds developed windslabs 10-40 cm deep since Friday. Heavy precipitation gave way to clearing skies and rapidly cooling temperatures early on Friday morning. Most areas saw heavy rain up to at least 2000 m this week. Above this it's possible that dense storm slabs and fresh cornices formed. Where it did rain, the snowpack is probably frozen solid with a dusting of fresh snow on top. The lower elevation snowpack has also thinned significantly. A weak layer of facetted snow on a crust was buried around 50-60 cm deep before the rain. This weakness may have been flushed out or may now be bridged by a solid ice crust; however, there is no new info on this interface so it would be wise to investigate its existence and strength before venturing into bigger terrain.

Problems

Wind Slabs

Strong Northeasterly outflow winds may have developed pockets of windslab at higher elevations where there is snow available for transport.

Be alert to conditions that change with elevation.>Avoid freshly wind loaded features.>Avoid travelling in areas that have been reverse loaded by winds.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Persistent Slabs

The layer of old crusts and facets that was buried on November 20th is now down about 100 cm in the alpine and continues to give hard sudden planar results in snow profile tests. This layer is expected to persist through this cold and dry spell.

Avoid convexities or areas with a thin or variable snowpack.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Nov 30th, 2014 2:00PM