Avalanche Forecast

Issued: Mar 5th, 2012 9:07AM

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

swerner, Avalanche Canada

Cariboos.

Summary

Confidence

Good

Weather Forecast

The region will continue to see unsettled weather conditions overnight Monday, bringing light snow, and moderate NW winds. Freezing levels will fall to valley bottom. Tuesday: Mainly dry conditions. A mix of sun and cloud in the morning. Increased cloud and light flurries during the afternoon. Freezing levels remain valley bottom. Wednesday/Thursday: Continued cloud, and light snow amounts. Ridgetop winds moderate from the NW. Treeline temperatures -12, rising to -4. Freezing levels fluctuating from valley bottom to 12-1500m Wed/Thurs afternoon.

Avalanche Summary

A natural avalanche cycle is under way, however poor weather is limiting observations. Natural, skier-remote and accidental avalanches were observed on Sunday to size 2. Avalanches reported throughout the week illustrate the unpredictable nature of persistent weak layers in the upper snowpack. Most failed on upper snowpack persistent weaknesses. These layers are touchy and are likely to fail under the new storm load, creating large or widely-propagating avalanches.

Snowpack Summary

Over the weekend, 60-100 cm snow has fallen. Strong winds and fluctuating temperatures are creating storm slabs and wind slabs on a widespread basis. Persistent weak layers (surface hoar, facets, crusts) buried in February are the main concern at all elevations and could be easily triggered by storm slabs, wind slabs or sluffs, or with a light additional load (like a sled or skier). Avalanches may be unexpectedly large, given the amount of fresh snow. Large cornices are forming, and may act as potential triggers for deep avalanches.

Problems

Storm Slabs

Continued snowfall with fluctuating temperatures are creating weak storm slabs. Storm slabs can be triggered by light loads (skiers, snowboarders, and sledders) They can be large, and destructive.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 6

Wind Slabs

Large amounts of available snow and strong winds are creating widespread wind slabs, even at treeline. Large cornices may also threaten many slopes.

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

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 6

Persistent Slabs

Persistent weaknesses in the upper snowpack are unpredictable and tricky to manage. They are becoming more reactive as storm snow overloads them. Be aware of the potential for surprisingly large, wide avalanches at all elevations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 7

Valid until: Mar 6th, 2012 8:00AM