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

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.

Avalanche danger is higher in places where the recent storm dropped the most snow.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Saturday is expected to be cloudy with a few flurries. A front on Sunday brings light snow, moderate SW winds and cooling temperatures. Snowfall and winds ease on Monday.

Avalanche Summary

Isolated wind slab avalanches were reported over the last few days. Several large persistent slabs failed naturally in the north of the region last weekend. This weak layer was reported to be reactive to skier triggering from thin spots, as well as heavy triggers such as a smaller avalanches or cornice failures.

Snowpack Summary

Recent snow has been heaviest in the west and north of the region, creating new storm slabs and wind slabs. It also rained up to 1500 m in the south and 1000 m in the north on Thursday, so the low elevation snow surface is likely to turn into a crust once temperatures drop. The recent snow overlies widespread hard old wind slabs, scoured surfaces, a thin sun crust on sunny aspects, and surface hoar in isolated sheltered and shady locations. A melt freeze 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.

Be alert to conditions that change with elevation. >Be aware of the potential for wide propagations due to the presence of hard windslabs.>Travel on ridges and ribs to avoid wind loaded areas. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 3

Persistent Slabs

A cornice fall 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, widely propagating avalanches due to the presence of buried weak layers.>Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Unlikely - Possible

Expected Size: 3 - 6