Avalanche Forecast

Issued: Apr 16th, 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 Thursday: Light to moderate snow or rain 5 cm tonight, 10 -15 cm/mm Thursday. The freezing level is around 1800 m. Winds are moderate from the South. Friday: Cloudy with flurries or showers. The freezing level is around 1600-1800 m. Winds are light to moderate from the West. Saturday: A mix of sun and cloud. The freezing level rises to 2200 m and ridge winds are light to moderate from the south.

Avalanche Summary

No new avalanches were reported on Tuesday. There was one report of a size 2.5 natural deep persistent slab in the Rossland Range that occurred on Sunday afternoon 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

A trace of new snow sits on a thick and solid melt-freeze crust in most places. This crust has been breaking down on all aspects up to around 2000 m and above this elevation on solar aspects most days. 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 steep lee terrain, especially where the new snow overlies a hard crust.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

Rain, warming, and periods of sun could be enough to wake up a deeply buried persistent weak layer and produce a very large avalanche.

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

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Apr 17th, 2014 2:00PM