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Avalanche Forecast

Jan 8th, 2015–Jan 9th, 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
2: Moderate
The avalanche danger rating below treeline will be moderate
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
2: Moderate
The avalanche danger rating in the alpine will be moderate
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 Inland.

Lingering storm instabilities remain a concern. Investigate local conditions in your area before committing yourself to avalanche terrain.

Confidence

Fair

Weather Forecast

The warm air aloft should break down on Friday and alpine temperatures should fall well below zero by the end of the day. Mostly cloudy conditions are expected during the day and alpine winds are expected to be moderate from the SW. On Friday night, a weak trough crosses the north coast and 4-8cm of new snow is possible in many parts of the region. On Saturday, mostly cloudy conditions, light flurries, and light alpine winds are expected.  Sunday should see a mix of sun and cloud and light alpine winds.

Avalanche Summary

On Wednesday, a natural size 2 storm slab was reported in the south of the region and isolated natural wind slabs from steep terrain to size 1.5 were reported in the north of the region.  On Tuesday, we received a report of numerous natural storm slab avalanches up to 1.5 at lower elevations. Natural avalanches activity is generally not expected on Thursday but isolated natural avalanches remain possible. The potential for human triggering is still a major concern for Friday.

Snowpack Summary

40-80cm of new snow fell during the storm system.  Strong winds, mainly from the S-SE, have striped windward slopes and built stiff wind slabs in leeward features. Below the storm snow may be a rain crust at lower elevations. In the mid-pack you may find a surface hoar layer, although it appears to be spotty in distribution. Near the bottom of the snowpack is a crust facet combo that was buried in mid-November.

Avalanche Problems

Storm Slabs

Heavy snowfall and strong winds have built both storm slabs and wind slabs in the south of the region. In the northern areas that received less snowfall, wind slabs are the primary concern.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Persistent Slabs

There are a couple persistent weak layers in the middle of the snowpack. Heavy triggers like cornice falls or smaller avalanches have the potential to trigger one of these deeper layers. These layers were most reactive in the north of the region.
Be aware of the potential for large, deep avalanches.>Use caution around convexities, ridge crests, rock outcroppings and anywhere else with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely - Possible

Expected Size: 2 - 6