Avalanche Forecast

Issued: Mar 25th, 2012 10:55AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Cornices, Loose Wet and Deep Persistent Slabs.

mpeter, Avalanche Canada

Kootenay Boundary.

Summary

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

Monday: Expect clouds to build, with a chance of flurries late in the day. More accumulations are expected over the extreme eastern edge of the region. Winds remain light southerly with the freezing level reaching 2000m. Tuesday & Wednesday: Mostly unsettled skies, with occasional light flurries and light southerly winds. The lingering cloud cover makes forecasting freezing levels uncertain; we could see anything between 1500-2000m. Expect total accumulations of 10-20cm.

Avalanche Summary

We have reports of loose, moist avalanches being triggered by solar radiation on sunny slopes. A fatal avalanche incident occurred in this region on Wednesday. We will post more details when they become available.

Snowpack Summary

The recent warm, clear weather has left us with an aggressive melt freeze crust on solar aspects well into the alpine while shady, dead north slopes have grown some small surface hoar and remain powdery. Today's predominant cloud cover will likely keep the softening of the crust to a minimum. The recent storm snow (now more than 72 hours old) has settled and bonded quickly. In recent snowpack tests, the early February surface hoar remains well preserved down 100-180cm and continues to yield sudden results. Although unlikely, triggering this layer would yield a very large, destructive avalanche.

Problems

Cornices

Cornices are very large and may fail with daytime warming. There is potential for triggering deep slabs on underlying slopes.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

2 - 6

Loose Wet

With lingering warm temperatures or if the sun pokes out we could see more wet sluffing. These small avalanches may trigger the deeper weaknesses.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Deep Persistent Slabs

The deep nature of the mid-February surface hoar layer makes potential avalanches triggered on this layer large and destructive. Avoid thin snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 8

Valid until: Mar 26th, 2012 9:00AM