Avalanche Forecast

Issued: Mar 9th, 2014 9:27AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs, Loose Wet and Deep Persistent Slabs.

Avalanche Canada bcorrigan, Avalanche Canada

Warming temperatures and Solar radiation with play a leading role in the avalanche hazard in the coming days. Pay special attention to large ripe cornices !

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Synopsis: An intense frontal system with subtropical moisture plowed it's way across the Province in the last 24 hours, pushing freezing levels above 2000 metres in some parts of the forecast area. The bulk of the moisture will be out of the forecast area later today.Tonight: Light to locally moderate precipitation in the forecast, freezing level should drop to 500m. Moderate to strong W winds.Monday: Mix of sun and clouds, possible flurries, light to moderate winds at ridge tops, freezing level may climb to around 1400m.Tuesday: Sunny with cloudy periods, no precipitation in the forecast, freezing around 1400m. winds from the west, light to moderate.Wednesday: Sunny with cloudy periods, freezing level rising to 1900m. Light ridge top winds.

Avalanche Summary

Rain, warm temperatures and additional loading from the recent storm, have produced numerous avalanches up to size 3. There are also reports of skier accidental and skier remote avalanches up to size 2. Many of these failed on the Feb.10 surface hoar / crust/ facet layers. There is ample opportunity now for a rider or skier to trigger an avalanche that might step down to any of the persistent weak layers in this years snow pack and produce a very large and destructive avalanche. Large cornices have been noted as a result of the high winds. As temperatures rise the chance of a cornice failure producing a large avalanche, will go up..

Snowpack Summary

The recent accumulation of up to 1 metre of storm snow is settling into a slab that now sits above a variety of old surfaces. There are buried facets on north aspects and sun crust on many south facing slopes. Rain up to 1800m has saturated the upper snowpack in some parts of the forecast area. At elevations above the freezing level strong SW winds have have formed winds labs in lee features. The surface snow has a "spongy" feel to it now, and there may be lighter snow underneath it making for "upside down" conditions, This will settle out with warm temperatures and time, improving skiing conditions. There are 3 persistent weak layers now buried in the snowpack, A January 28th layer of surface hoar, facets and crusts, a Feb.10th layer of surface hoar, facets and crusts, and the March 2nd layer of surface hoar, facets and crusts. Of these layers, the Feb. 10th layer appears to still be problematic, with field reports still indicating easy and sudden planar shears on this layer, especially on north aspects. The most recent weak layer, March 2nd, will be on the radar for a while as we wait for it to bond.

Problems

Storm Slabs

An icon showing Storm Slabs
80 to 100cm of touchy storm slab is still reactive to skier and rider triggering. South west winds are forming wind slabs on north east slopes. Sun crust on solar aspect is touchy and quite reactive.
The new snow will require several days to settle and stabilize.>Be alert to conditions that change with elevation.>Choose conservative lines and watch for clues of instability.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Likely

Expected Size

2 - 4

Loose Wet

An icon showing Loose Wet
Careful consideration to solar radiation on all solar aspects is highly advised during this warming trend.
The new snow will require several days to settle and stabilize.>Watch for terrain traps where small amounts of snow will acumulate into deep deposits.>Avoid steep, open glades in the forest.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Avoid unsupported slopes.>Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 10th, 2014 2:00PM

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