Avalanche Forecast

Issued: Mar 27th, 2013 11:08AM

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

mpeter, Avalanche Canada

Cariboos.

Danger will increase in the afternoon on sun exposed slopes due to intense radiation.

Summary

Confidence

Good

Weather Forecast

Thursday: Expect clear skies with mostly calm winds and alpine temperatures reaching -1. Freezing levels could climb to 1900m.Friday & Saturday: The pattern persists, with mostly clear skies, light southerly winds, no precipitation and rising freezing levels.

Avalanche Summary

Natural wet-loose avalanches up to Size 2 continue to be reported from throughout the region. This avalanche activity as well as natural cornice failure is expected to continue with warm and sunny weather throughout the forecast period.

Snowpack Summary

Clear, warm days and cold nights have brought the daily melt freeze cycle to the surface snow on sunny aspects and at lower elevations (below 1800m). Surface hoar is growing on high shaded terrain and the cold temperatures have broken down the windslabs in lee features in the alpine. Cornices are huge!The weak layer of buried surface hoar from March 10th is buried more than 100cm in most places, and is giving variable results in snow profile tests. Although unlikely to trigger, this deep persistent weakness remains a concern because of the potential for very large avalanches particularly with heavy triggers such as cornice falls or lighter triggers in thin snowpack areas.

Problems

Cornices

Cornices weaken with daytime warming.

Give cornices a wide berth when travelling on or below ridges.>

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

2 - 7

Loose Wet

Expect loose sluffs to run in the heat of the day when the sun is strong.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

Large loads like cornice falls, or lighter loads in thin snowpack areas may trigger the deeply buried March 10th surface hoar layer.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Be aware of thin areas that may propagate to deeper instabilites.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Mar 28th, 2013 2:00PM