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Avalanche Forecast

Jan 12th, 2017–Jan 13th, 2017
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
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
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: South Columbia.

Wind slabs may be reactive to rider triggering. The safest, best riding may be in lower elevation terrain sheltered from the wind.

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

The dominating arctic ridge is slowly breaking down as we transition to a more zonal (westerly) flow. Cloudy with some sunny periods, light-moderate westerly winds and slightly warmer alpine temperatures will persist through the weekend. A more significant change to come early next week.Friday/ Saturday/ Sunday: Mix of sun and cloud with mostly cloudy skies on Saturday. Ridetop winds will be light from the SW-W and alpine temperatures near -12.

Avalanche Summary

On Wednesday, some natural and numerous wind slab avalanches were reported up to size 2 on a variety of aspects. Loose dry sluffing was also noted from southerly slopes. Switching winds will likely promote a reverse loading pattern increasing the likelihood of rider triggered wind slab activity on a variety of aspects on Friday.

Snowpack Summary

Up to 30 cm of low density snow fell earlier this week. Moderate to strong southwest and then northerly winds have shifted these fresh accumulations into reactive wind slabs on leeward slopes. The mid-December facet/surface hoar persistent weakness can be found buried 70-120 cm deep and is generally considered dormant. However, we are still receiving occasional reports of sudden results in snowpack tests, suggesting that it has to potential to propagate into a large avalanche if triggered, particularly in shallow spots where this layer is closer to the snow surface. The lower snowpack is well bonded and features a thick rain crust near the ground.

Avalanche Problems

Wind Slabs

Wind slabs exist on a variety of aspects and have been reactive to rider triggers.
Watch for signs of instability such as whumpfing, or cracking. Avoid areas where the snow feels stiff or slabby.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2