Avalanche Forecast

Issued: Apr 8th, 2018 4:11PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs and Cornices.

jmcbride, Avalanche Canada

South Rockies.

New snow and rising freezing levels means elevated avalanche danger for the next few days. Choose conservative terrain and be especially wary of overhead hazards as the day warms or the sun shines.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

TONIGHT: Mostly clear. Ridge wind moderate to strong, west. Alpine temperature near -2. Freezing level 1000 m.MONDAY: Mostly sunny. Ridge wind moderate to strong, west. Alpine temperature near +3. Freezing level 2200 m.TUESDAY: Mostly cloudy. Ridge wind moderate to strong, southwest. Alpine temperature near +4. Freezing level 2600 m.WEDNESDAY: Mostly sunny. Ridge wind moderate to strong, west. Alpine temperature near 0. Freezing level 2000 m.

Avalanche Summary

There were no reported of avalanches in the region following Saturday's storm, however near Fernie; widespread storm slab and loose wet avalanche activity up to size 2.5 was reported on Sunday. The new snow was reactive to skier and explosive triggers on all aspects above 1400 m. And one natural size 2.5 was reported on an easterly aspect at 1550 m.On Friday both natural and easily skier-triggered wind slab releases up to size 1.5 were reported in the southern part of the region, while several loose dry avalanches were reported in the Crowsnest Pass area. Read recent MIN report here. Thursday in the Elkford area, recent small (size 1) loose/dry avalanches were reported on northerly aspects while loose/wet were observed on solar aspects. In the southeast corner of the region skier-triggered loose/dry avalanches were reported to be running far on a recently buried crust.

Snowpack Summary

With about 20 cm on new snow on Sunday morning, 20-40 cm of snow sits above a variety of crusts on all but high north aspects. Northern parts of the region have less new snow than southern parts. Wind has formed hard slabs in lee features, and in some cases the snow may be poorly bonded to the crusts.Multiple crusts exist within the top 100 cm of the snowpack. Some parts of the region may have a surface hoar layer roughly 60 cm deep on north aspects at treeline.A well settled midpack sits above sugary facets in many parts of the region, especially thin snowpack areas.

Problems

Storm Slabs

New snow and wind have formed storm slabs at all elevations. Expect these slabs to be touchy especially as freezing levels begin to rise. Watch for moist or wet snow releases on sunny slope and at lower elevations; these could trigger deeper slabs.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Use caution in wind-loaded, lee areas in the alpine and treeline. Storm snow will form touchy slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Cornices

Cornices are reported to be large and may become weak with rising freezing levels and sun exposure. A cornice failure has the potential to trigger large avalanches on the slopes below.

Give cornices a wide berth when travelling on or below ridges.Minimize exposure to overhead hazard from cornices.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Valid until: Apr 9th, 2018 2:00PM