Archived

Avalanche Forecast

Feb 10th, 2013–Feb 11th, 2013

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

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

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Glacier.

Strong sunshine will weaken the snowpack on solar aspects today. It may also cause cornices to fail. Be aware of what is above you; the slopes or cornices may be getting cooked. Minimize your exposure to overhead hazards.

Weather Forecast

A ridge of high pressure will result in strong solar today. Freezing levels may rise to 1900m, and temperatures in the alpine might get above zero. These factors will weaken the snowpack. On Monday, a cold front will bring increasing cloud and flurries. This will be followed by a warm front on Tuesday with thickening cloud and up to 15cm of snow.

Snowpack Summary

40cm of recent snow is settling and overlies a sun crust on steep solar aspects. Another layer down 80cm consists of stellar's and a sun crust on steep solar aspects. These layers have been reactive to ski cutting on steep unsupported features in Rogers Pass, and in the surrounding region failed causing several human triggered size 2 avalanches.

Avalanche Summary

Yesterday, a few size 2 avalanches were triggered on southerly aspects during brief periods of sunshine. 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.Today, strong solar will trigger natural avalanches.

Confidence

Intensity of incoming weather systems is uncertain

Avalanche Problems

Storm Slabs

Solar aspects are going get hit hard by the sun today. Natural avalanches are expected, particularly on steep slopes and around exposed rocks. It will also make skier triggering of the storm slab more likely. They may step down to a crust below.

Minimize exposure to sun exposed slopes when the solar radiation is strong.Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.

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

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Wind Slabs

Steady SW 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.

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 2