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Avalanche Forecast

Mar 31st, 2012–Apr 1st, 2012
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
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
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

Regions: Northwest Coastal.

Confidence

Fair - Intensity of incoming weather is uncertain on Monday

Weather Forecast

Sunday: a mix of sun and cloud with light snowfall - light and variable winds - freezing level at 700m Monday: light snowfall becoming mederate overnight - strong southeast winds - freezing level at 700m Tuesday: light snowfall - strong southeast winds - freezing level at 600m

Avalanche Summary

On Friday a few large to very avalanches were triggered by heli-bombing from the big terrain in Bear Pass. In the start zones they ran at the recent storm snow interface and gradually involved wet snow as they reached lower elevations. In the south of the region numerous dry loose snow avalanches to size 1.5 were also reported in steep terrain. In the same area a cornice fall triggered a size 2 slab on the slope below. Solar aspects are producing loose wet avalanches to size 2 with significant sun exposure.

Snowpack Summary

Light amounts of new snow override a variety of old surfaces that include wind slab, crusts and spotty surface hoar. Spring-like conditions have existed over the past several days forming crusts on solar aspects at all elevations that become moist under sunny skies during the day. Melt conditions exist on all aspects below 1000 m, with no significant re-freeze. This has developed a well settled upper snowpack with no significant layers of concern at this time. Below all this, down 60-120 cm exists a very spotty surface hoar/ facet interface. Operations from the field noted no recent activity on this layer. I suspect it's becoming dormant, but would be suspicious of large triggers like cornice fall, or under the weight of a sled and it's rider in specific areas. Cornices in the region are reported to be very large and potentially unstable.

Avalanche Problems

Cornices

Cornices are reported to be very large and potentially unstable at this time. A cornice fall could be destructive by itself, and may also act as a trigger on the slope below. Cornices are most likely to fail under sunny skies.

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

Elevations: Alpine.

Likelihood: Possible - Likely

Expected Size: 1 - 6

Loose Wet

With warmer spring temperatures, watch for loose wet snow avalanches in steeper terrain, especially when the sun is shining.

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Wind Slabs

Recently formed wind slabs may still be reactive in unsupported terrain at treeline and in the alpine.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 4