Avalanche Forecast

Issued: Nov 30th, 2014 8:16AM

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

pgoddard, Avalanche Canada

South Rockies.

What did you see over the weekend? We welcome your observations. Email forecaster@ avalanche.ca.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Monday/ Tuesday/ Wednesday: Very cold and mainly dry. Strong SW winds on Monday, becoming light for Tues/Wednesday.

Avalanche Summary

Explosives triggered two very large (size 2.5 and 3.5) slabs in the south of the region on Thursday around treeline. These failed on a weak layer of facets buried about a week ago. Explosives also triggered some 30-40cm deep size 2 storm slabs on Saturday between 2400 and 2600m on east-facing slopes. The odd naturally-triggered size 1-2 storm slab was also reported over the last few days.

Snowpack Summary

As we begin our forecasting season, we are working with very limited field data. If you have been out in the mountains, we'd love to hear from you. Please email us at forecaster@avalanche.ca.Half a metre or so of recent snow is likely to have been redistributed by wind into slabs on lee slopes. Natural avalanches may continue spilling down steep headwalls for a day or two. A weak layer (of facets over a crust) which formed during November's dry spell is now buried a metre or more down. Avalanches failing on this layer have the potential to propagate widely, leading to very large events.

Problems

Storm Slabs

Recent snow and wind may have left slabs on a variety of slopes. Watch for breakable or stiff-feeling snow, or smooth, bulbous-looking slopes. These may indicate wind slabs.

Avoid areas with overhead hazard.>Be cautious as you transition into wind affected terrain.>Be cautious of sluffing in steep terrain.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

A touchy weak layer is now buried a metre or so down in the snowpack. It may be reactive to the weight of new snow, wind-loading or the additional weight of a skier or sledder. Avalanches on this layer could be surprisingly large.

Choose regroup spots that are out of avalanche terrain.>Avoid convexities or areas with a thin or variable snowpack.>Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 6

Valid until: Dec 1st, 2014 2:00PM