Archived

Avalanche Forecast

Dec 10th, 2011–Dec 11th, 2011

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Purcells.

Confidence

Fair - Due to limited field observations

Weather Forecast

Sunday: Expect clearing skies, with light winds and temperatures reaching -10. Monday: Mostly clear, with winds turning westerly but remaining light. Freezing levels could reach 1200m. Tuesday: Expect clouds to build and light flurries to begin late in the day under southwesterly winds.

Avalanche Summary

No new avalanches.

Snowpack Summary

Surface hoar continues to grow and the cold weather is penetrating into the upper snowpack giving near surface facetting. Steep south facing slopes may have developed a thin sun-crust. Windslabs continue to lurk in lee areas in the alpine and open treeline. Snow depths are quite variable through the region with 130-150cm in the alpine. There is still concern for triggering the weak basal facets/depth hoar, as these layers have shown sudden collapse results in stability test in shallow areas.

Avalanche Problems

Wind Slabs

Stiff wind slabs in the alpine and open areas at treeline may be triggered by skiers and riders.

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

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 3

Persistent Slabs

The weak facetted layer near the ground may still be triggered by human activity with the common trigger points being convexities, rocks or clumps of small trees.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 5