Archived

Avalanche Forecast

Feb 26th, 2016–Feb 27th, 2016

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

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 Coastal.

Avalanche danger is one step higher in the north, where the recent storm dropped more snow.

Confidence

Moderate - Timing of incoming weather systems is uncertain

Weather Forecast

Expect a cloudy lull in the weather on Saturday before a front brings around 10-15 cm snow on Sunday. The freezing level is expected to be around 1000 m during the front, with strong southerly winds. Snowfall and winds ease on Monday.

Avalanche Summary

A cycle of naturally-triggered large wind slabs was observed on slopes lee to the south around Bear Pass on Thursday. Explosives also triggered size 1-2 storm slabs and wind slabs. Size 1-2 wind slabs were triggered naturally and by skiers on Wednesday, mostly at alpine and treeline elevations.

Snowpack Summary

Recent snow has been heaviest in the north of the region, creating storm slabs. These sit above old wind slabs, scoured surfaces, a thin sun crust on sunny aspects and surface hoar in isolated sheltered and shady locations. Previous strong southerly and outflow winds created widespread wind slabs on a variety of slopes at alpine and treeline elevations. These may now be buried and hard to spot. A hard crust buried around February 12th, down about 50-80 cm, extends up to about 2000 m. A layer of surface hoar buried late in January remains a lingering concern. Shallow snowpack areas may also have a weak base of facets near the ground.

Avalanche Problems

Wind Slabs

New and old wind slabs are lurking on many alpine and treeline slopes.

Travel on ridgetops to avoid wind slabs on slopes below.>Be alert to conditions that change with aspect and elevation. >Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 4

Persistent Slabs

A storm slab or wind slab could step down and trigger a deeply buried weak layer, creating a surprisingly large avalanche.

Avoid convexities or areas with a thin or variable snowpack.>Be aware of the potential for large, deep avalanches due to the presence of buried weak layers.>Dig down to find and test weak layers before committing to a big line. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 3 - 6