Archived

Avalanche Forecast

Jan 18th, 2013–Jan 19th, 2013

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

2: Moderate

The avalanche danger rating below treeline will be moderate

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: Northwest Inland.

Confidence

Fair - Due to limited field observations

Weather Forecast

Only trace amounts of new snow are expected for the forecast period. Winds should remain mainly light to moderate from the southwest with freezing levels hovering between 800-900m.

Avalanche Summary

There have been no recent avalanche observations.

Snowpack Summary

Rain below treeline has continued to maintain moist surfaces at lower elevations, although a nightly crust recovery is likely with forecast clear skies . Light to moderate amounts of new snow and strong to extreme winds at higher elevations have most likely formed hard windslabs in the lee of terrain breaks and ridges.A surface hoar layer that was buried at the end of December is now down 60-80 cm, and was reactive in some areas with recent warming. An otherwise strong mid-pack overlies a weak base layer of facets/depth hoar and the remnants of a crust.

Avalanche Problems

Wind Slabs

Strong westerly winds have created windslabs on lee terrain. With higher than normal wind values, watch for loading lower on the slope and in other unsuspecting locations.

Be cautious as you transition into wind affected terrain.>Be aware of the potential for wide propagations due to the presence of hard windslabs.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 4

Persistent Slabs

A layer of surface hoar buried at the end of December may still be reactive. Watch for triggering in sheltered, unsupported terrain.

Be aware of the potential for large avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 4

Deep Persistent Slabs

A deeply buried facet/crust weakness exists near the base of the snowpack. This layer could be triggered by large loads such as a cornice collapse or from a thin-spot trigger point.

Be aware of thin areas that may propagate to deeper instabilites.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 5