Avalanche Forecast

Issued: Nov 26th, 2012 9:32AM

The alpine rating is moderate, 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

Poor - Due to limited field observations

Weather Forecast

Tuesday: Mostly clear skies / Moderate to strong northwesterly winds / Freezing level at 1300mWednesday: Increasing cloud throughout the day with light snowfall developing by the evening / Strong southwest winds / Freezing level at 1400mThursday: Continued snowfall with heavier accumulations in the north of the region / Strong southwest winds / Freezing level at 1400m

Avalanche Summary

In a neighboring region there was a report of a size 2 natural loose snow avalanche. It occurred on a southeast aspect at about 2400m.

Snowpack Summary

Snow accumulations from last week varied from 25-50 cm, although the resulting storm/wind slabs have most likely gained considerable strength with the more recent break in the weather.A buried surface hoar layer has been reported. Although I am unsure of its distribution throughout the region, the average depth is about 60 cm from the surface and seems to exist in specific, sheltered locations. Below this (down 80-110 cm) sits the early November crust. Test results on this layer have been variable; however, some have shown sudden planar pops on facetted crystals at this crust interface, or within the crust sandwich.The snowpack depth in the alpine ranges from 130-225 cm. Treeline near 150 cm. A sharp transition exists below treeline, where the snowpack peters out around 1300 m.

Problems

Storm Slabs

Although last week's snow has had time to gain some strength, triggering storm/wind slabs is still possible, particularly in steep, unsupported terrain.

If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.>Avoid travelling in areas that have been reverse loaded by winds.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

There is a faceted crust that exists in the lower snowpack. Although no recent avalanches have been reported on this layer, triggering seems most likely on unsupported terrain at higher elevations or within start zones with smooth ground cover.

Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Nov 27th, 2012 2:00PM