Archived

Avalanche Forecast

Dec 3rd, 2017–Dec 4th, 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

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

Regions: Lizard-Flathead.

Recent storm snow accumulations are up to 50 cm. Storm slabs may be reactive to rider triggers. With limited observations and a variable snowpack use a conservative approach to route selection and terrain with low consequence.

Confidence

Low - Due to the number and quality of field observations

Weather Forecast

Monday: Mix of sun and cloud. Alpine temperatures near -10 and freezing levels at valley bottom. Ridgetop winds light from the west.Tuesday: Cloudy with sunny periods. Alpine temperatures near -8 and freezing levels at valley bottom. Ridgetop winds light from the west.Wednesday: Mix of sun and cloud. Alpine temperatures high of 0 degrees with freezing levels at valley bottom. Strong alpine temperature inversion.Expect strong inversions in the alpine up to 3000 m by Thursday. For detailed information visit the Mountain Weather Forecast.

Avalanche Summary

On Sunday, avalanche control with explosives triggered numerous size 1 dry loose avalanches above 1900 m from northeast aspects. Reactive storm slabs and dry loose avalanches may persist through Tuesday. Please submit your observations this weekend to the Mountain Information Network. Give info, get info.

Snowpack Summary

Up to 50 cm of accumulated storm snow has fallen on the crust that formed a week ago. The buried crust is supportive and approximately 10 cm thick. It extends from 1600 m to mountain top elevations on all aspects. Lots of uncertainty exists with the new snow sticking to the crust. Winds are likely redistributing the new snow above treeline and possibly forming wind slabs on leeward slopes and terrain features. The average snowpack depth at treeline is 60-80 cm while a deeper snowpack exists in the alpine.

Avalanche Problems

Storm Slabs

Storm slabs may have a poor bond to a buried crust down 30-60 cm and could be reactive to rider triggers. Dry loose avalanches may be able to push you into terrain features that have consequence.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Be careful with wind loaded areas, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2