Avalanche Forecast

Issued: Mar 6th, 2013 8:54AM

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

triley, Avalanche Canada

South Columbia.

The February 12th persistent weak layer continues to be a concern across the Interior Regions. Avalanches failing on this layer of buried surface hoar will be large and destructive.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain for the entire period

Weather Forecast

Overnight and Thursday: High cloud with light Northwest winds combined with light precipitation as a weak low pressure system tracks along the U.S. border. Freezing level rising to about 1100 metres.Friday: The ridge is expected to continue to influence most of the province bringing high overcast cloud to the South of the region and a trace of snow at higher elevations. Freezing level rising to 1300 metres.Saturday: Mostly cloudy with a chance of light precipitation in the afternoon.

Avalanche Summary

Some loose snow sluffing up to size 1.0 and a couple of size 2.0 wind slab releases were reported from Tuesday. There were also a couple of natural cornice falls to size 2.0 that did not release down to the deeply buried weak layers.

Snowpack Summary

A light dusting of new snow is sitting above various sun crusts and old storm slabs. The storm slab continues to settle, and is becoming more stubborn to trigger. The weak layer of surface hoar that was buried on February 12th is now down about 100-150 cms and continues to be triggered by light additional loads on Southerly aspects where it is sitting on an old sun crust. Larger loads like cornice fall or explosives have been able to trigger this layer on various aspects in the alpine and at treeline. If the we get a period of strong solar radiation, then we may see another cycle of natural activity on Southerly aspects resulting in large destructive avalanches.

Problems

Persistent Slabs

There is a weak layer of buried surface hoar down about 100-150 cms that may be triggered by large loads like re-grouping, cornice fall, or smaller avalanches in motion. Strong solar radiation may initiate this layer where it sits on a crust.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

4 - 7

Storm Slabs

The storm snow is settling and bonding, but may continue to be triggered by human activity. Periods of strong solar radiation may cause a cycle of storm snow releases on Southerly aspects.

The new snow will require several days to settle and stabilize.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 7th, 2013 2:00PM