Avalanche Forecast

Issued: Mar 24th, 2018 3:31PM

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

Avalanche Canada jmcbride, Avalanche Canada

It's still winter in the mountains. Watch for storm slabs that sit on crusts, surface hoar and/or facets at upper elevations. These slabs may be surprisingly deep on leeward slopes near ridge crests.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

SUNDAY: Increasing cloud and flurries in the afternoon. Accumulation trace. Ridge wind light, southwest. Temperature at treeline near -3. Freezing level 800 m.MONDAY: Cloudy, flurries. Accumulation 10-15 cm. Ridge wind light, southwest. Temperature at treeline near -2. Freezing level 1000 m.TUESDAY: Cloudy, flurries or light rain. Precipitation 10 -15 mm. Ridge wind moderate, southwest. Temperature at treeline +2. Freezing level rising to 1600 m.

Avalanche Summary

Thursday morning ski cutting work on the North Shore mountains produced loose, dry storm snow releases (size 1) above 1000 m and loose, wet size 1 releases below 1000 m.There have been no reports from the northern part of the region around Squamish, however it's likely that a natural avalanche cycle occurred in high alpine terrain with the recent storm.

Snowpack Summary

Around 45 mm of precipitation has fallen since Thursday. Rain transitioned to snow above 1000 m Thursday morning which produced about 25 cm of snow with light to moderate east/southeast wind. The warm to cold nature of the storm has allowed the new snow to bond well to the old surface up to treeline. The alpine likely saw very little if any rain and more snow/wind. Up high the new snow is likely sitting on a mixture of weak grains including a crust on solar aspects and potentially facets/surface hoar on polar aspects. Below the recent storm snow the snowpack is generally well settled and strong.

Problems

Storm Slabs

An icon showing Storm Slabs
Thursday's storm came in with moderate southerly wind that has likely formed slabs on alpine lee features that may remain sensitive to human triggering. Periods of sun may also induce natural avalanche activity on solar aspects on Sunday.
Minimize exposure to sun exposed slopes if solar radiation becomes strong.Watch for whumpfing, shooting cracks and recent avalanches which indicate unstable storm slabs.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 25th, 2018 2:00PM

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