Archived

Avalanche Forecast

Mar 9th, 2013–Mar 10th, 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

3: Considerable

The avalanche danger rating in the alpine will be considerable

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: Glacier.

Natural avalanches and cornice failures are expected today due to strong solar radiation.

Weather Forecast

It's looking like a beautiful bluebird day; clear skies, mild temps with the freezing level rising to 1500m, and moderate westerly winds are expected. This will be the strongest punch of sun the snowpack has received, and it will increase avalanche danger today. Unsettled conditions will return tomorrow, with increasing cloud and up to 10cm of snow

Snowpack Summary

A new crust formed yesterday on solar aspects below 1600m. 10cm of light snow overlies a rain crust to 1800m and settled snow and windslabs above. The settled storm slab is gaining strength. The Feb 12th PWL, now down over a meter, is of most concern on solar aspects where is overlies a crust, and on slopes where it has not yet avalanched.

Avalanche Summary

No new avalanches have been observed in the last 3 days. On a west aspect yesterday, skiers reported moist snow sluffing and snowballing on steep slopes below 1600m. Strong solar today will trigger loose avalanches on solar aspects and likely cause cornice failures, which may step down to deeper layers triggering large slab avalanches.

Confidence

Intensity of incoming weather systems is uncertain

Avalanche Problems

Loose Dry

Strong sunshine will trigger loose avalanches and make skier triggering more likely on solar aspects today. Solar triggered avalanches may step down to deeper layers, triggering large slab avalanches.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.

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

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Persistent Slabs

The surface hoar/crust layer from February is becoming less reactive; a function of it now being 1-1.5m deep and having avalanched in many areas. It is most likely to be triggered on solar aspects or by heavy triggers, resulting in large avalanches.

Caution around convexities or areas with a thin or variable snowpack.Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 2 - 4

Cornices

Cornices have grown very large and unsupported. Strong sun today will weaken them. Cornice failures are expected, and are in themselves a concern. Should these large loads trigger deeper layers, very large destructive avalanches are possible.

Do not travel on slopes that are exposed to cornices overhead.Give cornices a wide berth when travelling on or below ridges.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 2 - 3