Avalanche Forecast

Issued: Dec 14th, 2014 8:41AM

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

rbuhler, Avalanche Canada

Purcells.

Stability is improving but there are still avalanche problems out there. If you see anything interesting, please submit an observation using our new website tool. For more details see: http://goo.gl/Tj0xPC

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

High pressure persists for the forecast period. Monday should be mainly sunny with treeline temperatures around -6C and light SE winds. On Tuesday and Wednesday, conditions are much the same with a mix of sun and cloud, treeline temperatures around -8C, and light winds.

Avalanche Summary

A report on Sunday of a skier remotely triggering a size 2.5 avalanche from 5 meters away in the Dogtooth range alpine. This occurred at around 2300m in the alpine. Also reported was an explosive triggered size 2 persistent slab releasing around 60cm deep. On Saturday, explosive control at a ski area produced only surface sluffing; no slabs. Widespread natural avalanche activity was reported during the storm on Wednesday and Thursday.

Snowpack Summary

The rain-soaked snow surface has refrozen and created a melt-freeze crust up to around 2200 m. Above this elevation there may still be dry storm snow, which has probably been blasted around by strong southerly winds. In some areas the storm snow may be sitting on a layer of old surface hoar. The mid pack consists of settled snow, facets, and melt-freeze crusts (primarily lower elevations). The early November crust/facet layer is down around 1 m. Tests are suggesting that this layer is getting difficult to trigger but still has the potential to produce large avalanches.

Problems

Wind Slabs

Strong southerly winds last week created wind slabs in the alpine. Watch for wind loaded or cross loaded slopes well below ridge crests.

Use ridges or ribs to avoid pockets of wind loaded snow.>Use caution in lee areas in the alpine. Recent wind loading have created wind slabs.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

The likelihood of triggering a persistent slab has decreased with dropping temperatures but be wary of any slope that did not release during the storms or has been reloaded. Remote triggering of this layer may be possible.

Avoid common trigger zones including thin snowpack areas, near rocky outcrops, and steep alpine slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 15th, 2014 2:00PM