Avalanche Forecast

Issued: Dec 1st, 2014 8:39AM

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.

ghelgeson, 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

Synopsis: Fairly static weather pattern, the arctic high pressure centre persists over Southeastern BC for the next few days. The models suggest that cloud and precipitation will push into the southern half of the province Thursday night/Friday. Tuesday: Freezing Level: Valley Bottom; Precipitation: Nil; Wind: Treeline: Moderate, W/SW | Ridgetop: Strong, NWWednesday: Freezing Level: Valley Bottom; Precipitation: Nil; Wind: Treeline: Light, SW | Ridgetop: Moderate WThursday: Freezing Level: Valley Bottom; Precipitation: Nil; Wind: Treeline: Moderate, SW | Ridgetop: Moderate, W

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. We haven't had any newer reports, but I'd expect some further avalanche activity to occur this weekend in response to the recent snow and wind, with the chance of triggering a deeper weakness and creating a very large event.

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 fresh 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

Possible

Expected Size

1 - 6

Valid until: Dec 2nd, 2014 2:00PM