Avalanche Forecast

Issued: Mar 21st, 2013 10:13AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Wind Slabs and Loose Dry.

pmarshall, Avalanche Canada

Kootenay Boundary.

Summary

Confidence

Good

Weather Forecast

Synopsis: The pattern over the next five days starts out cool, convective and gusty. It will gradually turn milder, more stable and less windy towards SaturdayFriday: Freezing Level: 1000m Precip: 2/5mm – 4/10cm Wind: Light gusting mod NorthSaturday: Freezing Level: 1100m Precip: No significant precip expected. Wind: Light gusting mod NorthSunday: Freezing Level: 1000m Precip: : No significant precip expected. Wind: Light, NE

Avalanche Summary

The storm snow sluffed easily on the previous snow surface that is a thin crust. Reports of skier triggered, fast moving, loose snow avalanches to size 1.5 came in from across the region. Over the past few days numerous size 1-2 avalanches have been triggered naturally, by skiers, explosives and vehicles. In most cases, the new snow was failing on the hard crust below. Many were soft slabs where the wind had sifted the snow onto lee slopes, and several were loose dry avalanches.

Snowpack Summary

The boundary pulled a respectable 20 - 30 cm of snow from Wednesday's storm. Much of this snow came to rest on a thin crust that is present on almost all aspects with the exception being due North. A thick supportive crust can be found down 50 - 80 cm. A buried surface hoar down 80 - 90 cm continues to fail in a sudden planar fashion when tested. Potentially large fragile cornices loom over many slopes.

Problems

Wind Slabs

Don't let Fridays light winds lure you into complacency. Previously strong winds Weds/Thurs night will likely have formed fresh sensitive wind slabs on wind exposed slopes at both treeline and alpine elevations.

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Loose Dry

I expect active sluffing to remain a problem on wind sheltered slopes. Be sure you know where your sluff is in relation to yourself and others.

Be aware of party members below you that may be exposed to your sluffs.>Be cautious of sluffing in steep terrain.>

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Mar 22nd, 2013 2:00PM