Avalanche Forecast

Issued: Mar 26th, 2019 4:40PM

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

cgarritty, Avalanche Canada

North Columbia.

Variable snowfall from Tuesday's storm set up an equally variable wind slab problem over the region. Expect new snow to shed easily from steeper slopes when it gets its first shot of warmth and sunshine on Wednesday.

Summary

Confidence

High -

Weather Forecast

Tuesday night: Cloudy with continuing flurries bringing 5-10 cm of new snow. Light southwest winds shifting to northeast.Wednesday: A mix of sun and cloud. Light northeast winds. Alpine high temperatures around -4 with freezing levels to 1800 metres.Thursday: Sunny. Light northeast winds. Alpine high temperatures around -2 with freezing levels to 1900 metres.Friday: Sunny. Light west winds. Alpine high temperatures around 0 with freezing levels to 2000 metres.

Avalanche Summary

Preliminary reports from Tuesday in the Revelstoke area showed explosives control yielding mainly small (size 1-1.5) storm slab results, with slab depths of 10-20 cm. North to northeast aspects were the focal point and wide fracture propagations in these results were attributed to a poor bond between the new snow and the previous surface of crust.Monday's reports showed some skier triggered small wind slabs composed of new snow at ridgetop as well as continued small natural loose wet avalanches at low elevations where the snowpack remains isothermal (slushy).Looking forward, new wind slabs should be the primary avalanche problem, but one that may become touchier with warming and possible sun exposure on Wednesday. The same sun and warming will reinvigorate loose wet avalanche problems over the coming days, with new snow being the first to shed from steeper slopes as warming takes effect.

Snowpack Summary

Variable new snow amounts of 10-20 cm have accumulated above a surface of melt-freeze crust in most areas above 1500 metres, with the exception of north aspects above 2000 metres, where it may have landed on the last dry snow that remained after last week's warm up. Below about 1500 metres, new snow has buried variably isothermal (slushy) and crusty surfaces. Precipitation as rain has continued to saturate the snowpack that is for the most part isothermal and disappearing rapidly below about 1100 metres.The remainder of the snowpack is generally consolidated and strong. Exceptions may exist on north aspects above 2000 m, where a gradually strengthening layer of faceted grains buried 40 to 60 cm deep may still be preserved below an overlying slab of old and hard wind-affected snow.

Problems

Wind Slabs

New snow and south winds formed new wind slabs at higher elevations during the storm. This problem increases with elevation and is variable throughout the region with areas of locally enhanced new snow accumulation.

Use ridges or ribs to avoid pockets of wind loaded snow.Be careful around wind loaded pockets near ridge crests and roll-overs.

Aspects: North, North East, East, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 1.5

Loose Wet

Rising freezing levels and decreasing cloud cover will signal a return to active loose wet avalanche conditions on Wednesday. New snow from Tuesday's storm is expected to shed easily as warming takes effect, especially on steep, sun-exposed slopes.

Avoid exposure to terrain traps, where the consequences of a small avalanche could be serious.Use extra caution on slopes if the snow is moist or wet.This problem may affect shaded aspects where air temperatures exceed 0 degrees.

Aspects: East, South East, South, South West, West.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 1.5

Valid until: Mar 27th, 2019 2:00PM