Avalanche Forecast

Issued: Dec 13th, 2014 8:25AM

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

A ridge of high pressure will persist for several days. On Sunday, expect a mix of sun and cloud, treeline temperatures around -8C, and calm or light winds in the alpine. Monday and Tuesday will be much the same with mostly sunny conditions, treeline temperatures around -10C, and light winds in the alpine.

Avalanche Summary

Initial reports from Saturday suggest that avalanche activity has tapered off since the storm ended and temperatures dropped. Explosive control on Saturday morning 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 thick melt-freeze crust up to around 2100 m. A weaker breakable crust is being reported between 2100 and 2400 m. Above this elevation there may still be dry storm snow, which has probably been blasted around by strong southerly winds. In the Golden area a weak layer of surface hoar or facetted snow may be found under the storm snow at higher elevations. The mid pack consists of settled snow, facets, and melt-freeze crusts (primarily lower elevations). The mid-November weak layer (surface hoar, facets, and/or a crust) is buried 60-80 cm deep. Below this you will likely find a thick layer of sugary facets sitting on a solid rain crust from early November. The early November crust/facet layer did become reactive near Golden this week during the storm.

Problems

Wind Slabs

Use caution in the high alpine where most of the recent precipitation has fallen as snow. Watch for wind loaded or cross loaded slopes well below ridge crests from the past week of strong southerly winds.

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

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

The likelihood of triggering a persistent slab should be decreasing with dropping temperatures but be wary of any slope that did not release during the storms or has been reloaded.

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 14th, 2014 2:00PM