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Archived

Avalanche Forecast

Dec 6th, 2015–Dec 7th, 2015
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
4: High
The avalanche danger rating in the alpine will be high
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: Glacier.

Continued pulses of storm snow are loading on top of a widespread surface hoar layer.  Time for conservative route selection.

Weather Forecast

Next in a series of Pacific storms will impact southern interior ranges later today bringing another estimated 10cm of snow. The warming trend is forecast to continue each subsequent storm bringing a higher freezing level through the start of the new week.

Snowpack Summary

Close to 35cm of storm snow have fallen in the past 48hrs accompanied by strong S winds and continued mild temperatures. The resulting soft slab sits over a widespread weak layer of well preserved surface hoar. On steep solar aspects the surface hoar formed on top of a sun crust. Other weak layers to keep in mind are the Nov 5 SH down 90-110cm.

Avalanche Summary

Numerous avalanches were observed throughout the highway corridor. These slides have been running far, well down the runout fans.

Confidence

Timing of incoming weather systems is uncertain

Avalanche Problems

Storm Slabs

35cm of storm snow in past 48hrs along with warm temps and strong SW winds have formed storm slabs over a widespread weak surface hoar & facet layer. If triggered there is potential for large slab propagation.
Watch for whumpfing, hollow sounds, and shooting cracks.Be aware of the potential for wide propagations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 4

Wind Slabs

Expect windslabs on northerly aspects due to the multi hour strong south wind transport. If triggered these slabs have potential for wide propagation on the Dec 2nd SH layer.
Use caution in lee areas. Recent wind loading have created wind slabs.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3