Avalanche Forecast

Issued: Apr 17th, 2014 8:43AM

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

Peter, Avalanche Canada

Kootenay Boundary.

This bulletin was created using very limited field data. If you are out in the mountains, please send your observations to forecaster@avalanche.ca

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Tonight and Friday: Cloudy with flurries 5 cm tonight, 5-10 cm Friday. The freezing level is around 1400-1600 m. Winds are light gusting to moderate from the West. Saturday: Cloudy with sunny breaks and a chance of showers. The freezing level rises to 2500 m and ridge winds are moderate to strong from the south. Sunday: Cloudy with sunny breaks and a chance of showers. The freezing level rises to 2200-2400 m and ridge winds are moderate from the west.

Avalanche Summary

There are no reports or recent avalanche activity. On Sunday there was a report of a size 2.5 natural deep persistent slab in the Rossland Range in response to strong solar radiation and warm temperatures. This avalanche released on a steep southeast aspect at around 2100 m and likely failed on the mid February weak layer. It's a good reminder of the potential for large deep avalanches under certain conditions.

Snowpack Summary

10-15 cm of moist new snow (with more expected) sits on a solid and supportive melt-freeze crust on most aspects above around 1600-1700 m. Below this elevation the snow is probably wet. Moderate westerly winds may form new wind slabs in exposed lee and cross-loaded terrain near ridge crests. The late January/early February persistent weak layer is deeply buried and has not produced avalanches in this region for some time now. Cornices are large in some areas and should be given a wide berth.

Problems

Wind Slabs

It may be possible to trigger fresh wind slabs in exposed lee and cross-loaded slopes, especially where the new snow overlies a slick crust.

Use ridges or ribs to avoid pockets of wind loaded snow.>Avoid freshly wind loaded features.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

This problem is unlikely but it remains on the radar. We could see this wake up again this weekend with forecast warming and strong solar radiation.

Use caution on big alpine slopes, especially around thin areas that may propagate to deeper instabilities.>Be aware of the potential for large, deep avalanches due to the presence of buried persistent weak layers.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Apr 18th, 2014 2:00PM