Avalanche Forecast

Issued: Mar 27th, 2013 4:00PM

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

Snow Safety, Parks Canada

Banff Yoho Kootenay.

We are entering early spring conditions. Steep solar slopes will see the hazard rise to Considerable or High in the afternoons. Start early. SH

Summary

Weather Forecast

Light W to NW winds, no snow, mainly clear skies, and freezing levels to 2000m+ on Thursday, higher on Friday.Â This will increase activity on solar aspects.

Snowpack Summary

Kootenay Park today, S through W slopes developing variable melt freeze crusts, thickest on steep W aspects. 20cm powder snow on N aspects over temperature crust up to 1800m. Well settled snowpack at 2300m. Moist snow on solar aspects by 11AM. E of divide settled wind slabs over basal facets. Supportive travel with variable sun crust up to 2700m.

Avalanche Summary

Afternoon loose wet avalanches on solar slopes in Kootenay within last 24hrs up to size 2.Â Most started in steep terrain at treeline and below, with adjacent lower angled slopes not running. Â A report of a cornice failure on the N couloir of Bow peak yesterday at 10AM sending one skier tumbling down the gully 200ft in the debris with no injuries.

Confidence

The weather pattern is stable on Thursday

Problems

Loose Wet

Occurring in the afternoons, activity has been mainly isolated to very steep slopes at treeline and below. As freezing levels rise over the next few days, we should start to see more natural avalanches occurring in the alpine.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.Avoid ice climbs that are exposed to steep rocky terrain on solar aspects.

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

In shallow snowpack areas, particularly east of the divide, whumphing has subsided. However, recent avalanche activity from cornice falls and warm temperatures shows it is still a layer to be respected.

Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Cornices

Cornice failures have increased in number as the freezing levels rise. They may trigger an avalanche, or be an avalanche themselves in couloirs.

Cornices become weak with daytime heating, so travel early on exposed slopes.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Mar 28th, 2013 4:00PM