Archived

Avalanche Forecast

Dec 26th, 2013–Dec 27th, 2013

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

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: South Coast.

Confidence

Fair - Intensity of incoming weather systems is uncertain on Friday

Weather Forecast

Friday: Light to locally moderate snowfall / Moderate southwest winds / Freezing level at 1200mSaturday: Overcast skies / Light winds / Freezing level at 1000mSunday: Mix of sun and cloud / Light winds / Freezing level at 1100m

Avalanche Summary

No new avalanches have been reported.

Snowpack Summary

Snowpack depths vary greatly across the region with 130cm reported at treeline in the Northern Cascades but only about 50 cm along the Duffy. In general, the snowpack across the region is significantly thinner than average for this time of year. Terrain below treeline is still mostly below threshold for avalanche activity.Recent moderate storm accumulations have now gained considerable strength and surface instabilities are likely specific to smaller, upper-elevation windslabs from light accumulations and steady moderate southwest winds. Below treeline light rain has moistened what little snow there is. Previous weak interfaces within the snowpack appear generally well bonded and have been unreactive to recent snowpack tests. The exception to this seems to be in the north of the region where touchy surface hoar buried on December 12th sits about 30cm below the surface. This seems to be the interface to watch as the overlying slab develops. Early season riding hazards such as rocks, stumps and logs are lurking below the surface at treeline elevations and below.

Avalanche Problems

Wind Slabs

Light to locally moderate accumulations and wind forecast for Thursday night and Friday will create new wind slabs. Watch for triggering in the lee of ridgecrests, terrain breaks and in gullies.

Be alert to conditions that change with elevation.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Persistent Slabs

Reports from the Duffey area indicate a touchy layer of buried surface hoar now sits under about 30cm of snow. This is likely the layer to watch as the overlying slab develops.

Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2