Avalanche Forecast

Issued: Nov 24th, 2012 4:00PM

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

Brad White, Parks Canada

Banff Yoho Kootenay.

There is just enough load on the November 6 crust which is down approximately 40-60 cm to become a danger for triggering. Use caution and avoid very steep lee slopes particularly just at treeline. JBW

Summary

Weather Forecast

The forecast calls for mainly sunny weather over the next few days with high pressure ridging and some convective showers. The main storm energy will be to the south. The winds will be westerly and still moving snow

Snowpack Summary

Up to 60 cm storm snow over the past 5 days has settled into a soft slab approximately 30-40 cm thick. In open areas wind has blown the storm snow into a soft slab with wind slabs on north and east aspects. Nov. Cr down 40-60 now.

Avalanche Summary

Several Na out of steep terrain in the alpine during the storm up to size 2.5, some failing on Nov. Cr and some on storm snow. Avalanche control today produced up to size 2 slabs as much as one metre deep in lee areas.

Confidence

Due to the number of field observations

Problems

Wind Slabs

20-40 cm thick soft and hard slabs, reactive to explosives and ski cuts and restricted mostly to immediate lee of ridge crests or in open areas Slab was stiffer today with longer propagations, but still in the size 2 range.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

The load on this layer is in the critical range. Open areas at treeline have just enough stiffness in the slab to have the potential for deep triggering and propagation. Several Na, skier and explosive avalanches up to size 2 in the last 36 hrs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Nov 25th, 2012 4:00PM