Archived

Avalanche Forecast

Mar 21st, 2012–Mar 22nd, 2012

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

2: Moderate

The avalanche danger rating below treeline will be moderate

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

Regions: Northwest Coastal.

The avalanche danger is expected to rise during the day if we see prolonged sunny periods.

Confidence

Fair - Due to variable weather conditions

Weather Forecast

Thursday: Scattered flurries with sunny breaks - 2-5cm. The freezing level should rise to 800m during the day. Winds are moderate from the southeast. Friday and Saturday: A ridge of high pressure builds in giving drier and sunnier conditions. The freezing level bounces from valley bottom overnight to around 1000m during the day. Winds are generally light from the south.

Avalanche Summary

Reports from Tuesday include several skier controlled slab avalanches up to Size 1.5 (15-30cm deep), primarily from wind loaded terrain features. There was also one natural Size 2 avalanche observed on a north aspect with a 50cm crown.

Snowpack Summary

20-40cm of new snow sits on the previous snow surface which included a sun crust on southerly aspects, surface facets or surface hoar in cool shady areas, and pockets of wind slab in exposed terrain. A variety of potential weak layers exist between 60 and 120cm deep. These include surface hoar or facets. There has been no recent activity on these layers but they could wake up with heavy triggers like a large cornice chunk or a snowmobile digging its track in. Cornices in the region are reported to be very large and potentially unstable.

Avalanche Problems

Wind Slabs

New wind slabs may be triggered in exposed lee and cross-loaded terrain.

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

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 1 - 4

Cornices

Cornices are reported to be very large and potentially unstable at this time. A cornice fall could be destructive by itself, and may also act as a trigger on the slope below.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 6

Loose Wet

Loose wet avalanches are likely on steep sun exposed slopes if the sun is shining.

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

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 3