Avalanche Forecast

Issued: Nov 29th, 2012 9:40AM

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

jlammers, Avalanche Canada

South Columbia.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain for the entire period

Weather Forecast

Friday: Moderate snowfall / Moderate southwest winds / Freezing level at 1500mSaturday: Heavy snowfall / Moderate southwest winds / Freezing level at 1400mSunday: Light snowfall / Light southerly winds / Freezing level at 1100m

Avalanche Summary

No recent avalanche activity to report. We welcome all field observations at forecaster@avalanche.ca.

Snowpack Summary

Up to 10cm of new snow fell on Wednesday night with light to locally moderate south/southwesterly winds. Forecast wind and snow will add some punch to this developing wind/storm slab which sits over a variety of surfaces that may include surface hoar, a sun crust on steep solar aspects, and well settled storm snow from last week. Deeper in the snowpack you might find a thin, spotty surface hoar layer between 50 and 85 cm down. As well, the early November rain crust now sits over 100cm down in most locations (at treeline and above) and may exist in combination with facets. These layers seem to have been unreactive in recent days, but may have the potential to 'wake-up' with additional loading.The snowpack depth in the alpine ranges from 130-225 cm. Treeline near 150 cm.

Problems

Storm Slabs

Snow and wind forecast for the next few days will add to the size and reactivity of a developing wind/storm slab that overrides a variety of potentially weak surfaces.

Use extra caution during periods of heavy loading from new snow, and wind.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Persistent Slabs

Although the likelihood of a release is low, the consequences of a persistent slab avalanche could be significant. These layers may wake-up with additional loading.

Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Nov 30th, 2012 2:00PM