Archived

Avalanche Forecast

Mar 19th, 2012–Mar 20th, 2012

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

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.

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

Tonight and Tuesday: Moderate snowfall - Approximately 5cm overnight and an additional 5-15cm on Tuesday. The freezing level (FL) is around 500m and winds are moderate from the S-SW. Wednesday: Unsettled conditions with convective flurries - 5-10cm. FL is near 500m. Winds easing to light from the south. Thursday: Mainly cloudy with light flurries. No significant accumulation.

Avalanche Summary

There was one report of a Size 2.5 natural slab avalanche on a SW aspect along the highway corridor west of Terrace. The crown was reported to be 45-70cm deep. Otherwise there were no new observations.

Snowpack Summary

The soon to be buried snow surface includes 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 form in exposed lee and cross-loaded terrain on Tuesday.

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