Archived

Avalanche Forecast

Dec 31st, 2013–Jan 1st, 2014

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

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: South Coast.

Confidence

Fair - Intensity of incoming weather systems is uncertain on Thursday

Weather Forecast

Wednesday: Cloudy with scattered light flurries increasing to moderate snowfall overnight. Strong SW winds are expected with the onset of significant precipitation and freezing levels should hover around 900m. Thursday: Snow with 5-10cm of total accumulation. Strong SW winds and freezing levels around 1000m, but above freezing temperatures could extend as high as 1700m. Friday: Continued light to moderate snowfall, especially for the Cascades. Moderate NW winds and freezing levels dropping to 600m.

Avalanche Summary

No avalanches were reported on Monday.

Snowpack Summary

Snowpack depths vary greatly across the region with 165cm at treeline in the Cascades but only about 65cm in the Duffey Lake area. 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. Snowpack testing on a SSE facing slope at 2000m in the Duffey Lake area on Monday produced easy to moderate, sudden collapse compression test results, and a RB3, whole block release Rutschblock result down 20cm on the mid-December surface hoar, as well as moderate sudden planar and RB1 results down 46cm on the late-November facets where they were found above a hard crust. However, these weak interfaces appear generally well bonded in the Cascades.Early season riding hazards such as rocks, stumps and logs are lurking below the surface at treeline elevations and below.

Avalanche Problems

Wind Slabs

Wind slabs that formed on Tuesday are likely limited to the immediate leeward side of ridgecrests, but widespread fresh touchy wind slabs are expected to start forming Wednesday afternoon.

Avoid freshly wind loaded features.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine.

Likelihood: Unlikely - Possible

Expected Size: 1 - 2

Persistent Slabs

Primarily in the northern part of the region. Persistent weaknesses may be particularly touchy where there is an associated crust.

Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.>Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.>Use caution in shallow snowpack areas where triggering is more likely.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 2