Archived

Avalanche Forecast

Mar 9th, 2012–Mar 10th, 2012

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Northwest Coastal.

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Saturday: 15-25cm of new snow - Strong southerly winds - Freezing level at 600m Sunday: Light snowfall - Light to moderate southerly winds - Freezing level at 400m Monday: Some clearing - Light and variable winds - Freezing level at surface

Avalanche Summary

A few skier-triggered size 1 avalanches were reported on Thursday running on the March 1st surface hoar layer. Storm snow avalanches up to size 3 were reported from the big terrain around Bear Pass. Otherwise, no new avalanches to report. This may speak more to the lack of observations than actual conditions. Expect further avalanche activity with weather forecast for Saturday.

Snowpack Summary

Strong westerly winds are keeping wind slabs fresh and weak on lee aspects. The early February persistent weak layers seem to be bonding, but remain a concern in some parts of the region. Persistent slabs may be reactive to human triggers, particularly below treeline on isolated and sheltered steep terrain where buried surface hoar may be preserved. Surface hoar buried at the beginning of March has also started to become reactive in some areas as the over-riding slab develops. Cornices in the region are reported to be large and unstable.

Avalanche Problems

Wind Slabs

Forecast weather is expected to contribute to ongoing wind slab development. Watch for wind slabs on lee features in the alpine and at treeline.

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

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 1 - 5

Storm Slabs

Any new snow is expected to initially bond poorly.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 4

Persistent Slabs

Although persistent slabs are not widespread in the region, heavy loading may reinvigorate these weaknesses where they exist. Any avalanches failing on these layers are expected to be large and destructive.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 2 - 7