Avalanche Forecast

Issued: Nov 28th, 2014 8:33AM

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

Avalanche Canada rbuhler, Avalanche Canada

A Special Avalanche Warning has been issued for the weekend. Now is an important time to exercise restraint and stick to low angle terrain.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

An Arctic high pressure system dominates the weather pattern for the weekend. Cold and dry is the theme for the next few days.Saturday: A mix of sun and cloud, treeline temperature around -15, light N alpine windsSunday: Sunny, treeline temperature around -20, light NW alpine windsMonday: Mostly sunny, treeline temperature around -15, light SW alpine winds

Avalanche Summary

Widespread natural activity up to size 2 on all aspects above 1800m was reported on Thursday and early Friday in the Invermere area. Explosives and ski cuts produced further results on Friday. Observations from other parts of the region are very limited. If you are out in the mountains and observe activity, please send your observations to forecaster@avalanche.ca.

Snowpack Summary

This is an estimate of what the snowpack may look like based on a few old observations and previous weather. If you plan on heading into the mountains be sure to supplement this with your own observations and please pass along any data you collect (forecaster@avalanche.ca).Around 40-60 cm of recent storm snow has fallen in the past few days. This new snow may be sitting on a layer of surface hoar, facets, and/or a sun crust (similar to the South Columbia). Below this you will likely find a 15-25cm thick layer of sugary facets, which is sitting on a solid rain crust from early November. Recent strong and variable winds have probably created dense wind slabs in exposed terrain and resulted in variable snow distribution in the alpine. At lower elevations, expect travel to be difficult and potentially hazardous as many early season hazards are exposed or lightly buried (stumps, logs, rocks, open creeks, etc).In the southern part of the region, warming and rain has occurred to high elevations in the mountains.  The northern Purcells likely stayed below freezing and this is where the current danger ratings are most representative. 

Problems

Storm Slabs

An icon showing Storm Slabs
A slab around 40-60cm thick sits on a touchy weak layer and is producing large avalanches. Strong alpine winds have loaded leeward features in exposed terrain creating touchy wind slabs.
Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 4

Valid until: Nov 29th, 2014 2:00PM

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