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Archived

Avalanche Forecast

Feb 14th, 2018–Feb 15th, 2018
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
3: Considerable
The avalanche danger rating below treeline will be considerable
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
3: Considerable
The avalanche danger rating below treeline will be considerable
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
3: Considerable
The avalanche danger rating below treeline will be considerable

Regions: Northwest Coastal.

Snowfall amounts for Thursday are uncertain, if amounts received exceed forecasted values the avalanche danger will be "High".

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

THURSDAY: Snow. Accumulation 5-15 cm. Ridge wind moderate to strong, southwest. Temperature -6. Freezing level 300 m.FRIDAY: Mix of sun and cloud, light flurries. Accumulation up to 5 cm. Ridge wind light, south. Temperature -7. Freezing level 400 m.SATURDAY: Mix of sun and cloud. Ridge wind light to moderate, northeast. Temperature -9. Freezing level 200 m.

Avalanche Summary

Numerous professionals across the region are reporting that intense loading during Tuesday's storm triggered a widespread natural avalanche cycle up to size 3, with at least one avalanche running beyond it's historical runout distance.

Snowpack Summary

Approximately 40-60 cm of new snow has fallen across the region since Tuesday with the highest snowfall amounts in the Terrace area.This new snow sits on a wide array of surfaces - including wind scoured from strong and variable winds during the long weekend, and fresh wind slabs at higher elevations on lee (downwind) slopes as well as facets and surface hoar in sheltered locations at treeline and below, and suncrusts on steep solar aspects.A 5-20 cm thick crust that was buried early February and can be found 60-110 cm below the surface on all aspects up to 1400 m. A weak layer buried in mid-January is 120-150 cm below the surface and remains a concern. In most areas this layer is a crust, but it may also be surface hoar in sheltered areas at tree line and below. This layer may remain reactive as it adjusts to the weight of the new snow.In thinner snowpack areas (north and inland), deeper crust / surface hoar layers that were buried in December and early January may still be a concern. They are buried over 150 cm below the surface, but could still be reactive and triggered from shallow spots.

Avalanche Problems

Storm Slabs

Recent heavy snowfall and strong winds have formed widespread storm slabs that are both deep and reactive.
The new snow will require several days to settle and stabilize.Avoid all avalanche terrain during periods of heavy loading from new snow or wind.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 3

Persistent Slabs

A weak layer exists 130-180 cm below the surface. It may still be possible for rapid loading from snow on wind to trigger this layer, or for a storm slab release to step down to this layer resulting in a very large avalanche.
Minimize overhead exposure during periods of heavy loading from new snow, wind.Avoid lingering in runout zones. Large avalanches may run long distances.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely - Possible

Expected Size: 2.5 - 4