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Archived

Avalanche Forecast

Dec 13th, 2017–Dec 14th, 2017
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
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
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.

Treeline and Alpine elevations are wind hammered. The best snow quality for riding can be found on shady, sheltered slopes.

Confidence

Moderate - The weather pattern is stable

Weather Forecast

Thursday: Cloudy with sunny periods. Alpine temperatures show a high of plus 4 degrees and freezing levels 2000 m. Ridgetop wind strong from the southwest.Friday: Mix of sun and cloud. Trace of new snow 3-10 cm. Alpine temperatures -2 and freeing levels 1100 m. Ridgetop wind strong from the west.Saturday: Cloudy with sunny periods. Alpine temperatures near -2 and freezing levels 1900 m. Ridgetop winds mostly light, with strong gusts from the southwest.

Avalanche Summary

No recent avalanche observations. On Monday, a size 2 slab avalanche was reported. At this point we're not sure if it was skier triggered or a natural. The crown depth was 30-50 cm deep by 30 m wide and ran 150 m. The terrain feature was a steep, wind loaded convex roll above treeline in the "Little Simpson" area.Please submit your information to the Mountain Information Network. Give info get info.

Snowpack Summary

Snow surfaces are highly variable throughout the region. Solar and temperature crusts have formed on sun-exposed slopes, while stiff, stubborn wind slabs linger in leeward alpine terrain. Feathery surface hoar and surface facets have formed below treeline up to 1500 m. Approximately 30-50 cm of snow sits on two crusts that were buried near the end of November. These crusts are widespread and extend into the alpine. Although snowpack tests have previously shown hard results at these crust interfaces, more recent observations have been limited. Below these crusts, a well settled mid-pack overlies the late October crust near the base of the snowpack. This "crust/facet combo" layer is widespread and has not been reactive to rider and remote triggers since the end of November.Average snowpack depths now total 80-140 cm at treeline elevations and up to 160 cm in the alpine.

Avalanche Problems

Wind Slabs

New wind slabs may be rider triggered. Watch for triggering in higher elevation, wind-exposed terrain.
Be cautious as you transition into wind affected terrain.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2

Deep Persistent Slabs

The late October crust lies near the base of the snowpack with a thin layer of weak, sugary snow above it. This layer should be on a strengthening trend, but a heavy trigger in a thin snowpack area may still be enough to cause it to react.
Be especially cautious in shallow snowpack areas where triggering a deeper layer may be easier.Be aware of the possibility for full depth avalanches due to deeply buried weak layers.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 3