Avalanche Forecast

Issued: Mar 8th, 2014 8:20AM

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

bcorrigan, Avalanche Canada

Kootenay Boundary.

The hazard may change if more rain and higher freezing levels occur in the forecast area.

Summary

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

Synopsis: An intense frontal system with subtropical moisture is forecast to arrive on the BC coast in the next 24 hrs. Warm air preceding the Pacific frontal system has already pushed freezing levels up to 2000 metres in some parts of the forecast area.Tonight: Cloudy with flurries and possible 10 to 20cm of precipitation. Strong SW winds and freezing levels climbing to 1700m.Sunday: Cloudy, snow flurries mixed with rain at lower elevations, 5 to 10 cm of snow, winds gusting to strong at ridge tops, freezing levels may climb to 2100m.Monday: Mix of sun and clouds, No precipitation in the forecast, light to moderate winds at ridge tops, freezing level drops to around 1500m. Tuesday: Sunny with cloudy periods, no precipitation in the forecast, light winds at ridge top, freezing level down to around 14500m.

Avalanche Summary

As a result of the rain, warm temperatures and additional snow loading from the most recent storm, numerous avalanches up to size 3 have been reported in the past 24 hrs. In some cases failing through the seasons snow pack to ground. There are also numerous 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 that now exist in this years snow pack and produce a very large and destructive avalanche..

Snowpack Summary

The recent storm snows are rapidly 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. Rains up to 1800m have saturated the upper snowpack. At elevations above the freezing level strong SW winds have have formed winds labs in lee features. 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. All of these layers have been noted in recent avalanche activity.

Problems

Storm Slabs

Warm temperatures are encouraging the settlement of the storm snow into a soft slab that overlies a variety of potentially weak surfaces. Moderate to strong SW winds have formed stiff wind slabs in lee features.

Choose conservative lines and watch for clues of instability.>Be alert to conditions that change with elevation.>The new snow will require several days to settle and stabilize.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Likely

Expected Size

2 - 4

Loose Wet

Watch for terrain traps where small amounts of snow will acumulate into deep deposits.Avoid steep, open glades in the forest.

Avoid steep, open glades in the forest.>Watch for terrain traps where small amounts of snow will acumulate into deep deposits.>The new snow will require several days to settle and stabilize.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

The Feb. and early March weak layers still remain reactive in some areas and may produce large, destructive avalanches. Warm temperatures, and the loading by new snow may 'wake up' these weak layers. Very large avalanches are possible.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>Avoid unsupported slopes.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 9th, 2014 3:00PM