Avalanche Forecast

Issued: Feb 11th, 2013 8:00AM

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

Parks Canada Danyelle Magnan, Parks Canada

Summary

Weather Forecast

We will see increasing cloud today as a frontal system enters the region. Expect light flurries,  alpine temps just below -10, and moderate westerly winds. On Tuesday we expect 5-10cm of snow with strong westerly winds intensifying loading.  On Wednesday, the clouds should start to clear again with temperatures dropping to -20 in the alpine.

Snowpack Summary

A new sun crust will have formed on steep solar aspects yesterday. In the upper snowpack, layers down 40 (crust) and 80 (crust on solar and large stellars/ pockets of surface hoar elsewhere) have been reactive to ski cutting on steep unsupported features in Rogers Pass, and in the surrounding region caused several human triggered size 2 avalanches.

Avalanche Summary

Yesterday, there was a widespread avalanche cycle. They were loose avalanches size 1.5 to 2.5, on solar aspects, triggered by strong sunshine. On Saturday, skiers triggered size 1.5 slab avalanches on the SE face of 8812. Recent natural avalanches on N and E aspects have been size 2-2.5 and triggered by loading due to steady moderate SW winds.

Confidence

Problems

Wind Slabs

An icon showing Wind Slabs
Steady winds continue to transport snow and trigger natural avalanches from steep lee slopes. Isolated pockets of wind slab will have formed immediately below ridgecrests; most likely in serious terrain where a ride would have severe consequences.
Be cautious as you transition into wind affected terrain.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Storm Slabs

An icon showing Storm Slabs
Last weeks snow has settled into a slab. The layers of concern below vary by aspect, but are most likely to be triggered on steep southerly aspects where buried crusts exist. The slab is stubborn to trigger but large avalanches are possible.
Choose well supported terrain without convexities.Choose regroup spots carefully.

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Feb 12th, 2013 8:00AM