Avalanche Forecast

Issued: Mar 22nd, 2018 5:48PM

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

Avalanche Canada ghelgeson, Avalanche Canada

Strong southerly wind, continued precipitation and lowering freezing levels are expected to drive fresh storm slab development through Friday. Wind slabs are likely to be found in unusual locations, welcome back to winter!

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

A rather complex weather pattern continues to deliver precipitation to the South Coast.  Lower freezing levels Thursday night should allow for snow at lower elevations.  Precipitation is expected to diminish Friday night with a brief window of clearing Saturday.THURSDAY NIGHT: Freezing level holding at 500 m, moderate to strong south/southwest wind, 10 to 15 more mm of precipitation.  FRIDAY: Broken cloud cover, freezing level holding near 500 m, moderate southwest wind, 15 to 20 mm of precipitation expected.SATURDAY:  A few clouds, freezing level beginning at 500 m rising to 1000 m, light south/southwest wind, no significant precipitation expected. SUNDAY:  Scattered cloud cover, freezing level holding at 700 m, light to moderate west/southwest wind, a few mm of precipitation possible. 

Avalanche Summary

New rain, snow and wind Wednesday night into Thursday likely initiated fresh avalanche activity that was probably most pronounced in higher elevation terrain.

Snowpack Summary

Around 30 mm of rain transitioning to up to 20 cm of snow has fallen as of Thursday afternoon with wind out of the southeast.  This snow sits on a mixture of weak grains including a slippery crust that is present at all elevations on solar aspects and low elevation polar aspects. On polar aspects at and above treeline the new storm snow may be burying facets and surface hoar.  The storms transition from warm to cold should be great for our snowpack in the long term, but fresh touchy storm slabs are expected to continue to build Thursday night and Friday. Below any recent snow accumulations, the overall snowpack is well settled and strong.

Problems

Storm Slabs

An icon showing Storm Slabs
Strong to extreme southerly wind combined with continued snowfall through Friday will form fresh slabs that are not expected to bond well to the mix of crusts, surface hoar and facets that they rest on. Watch for wind slabs in unusual locations.
The new snow will likely need a day to settle and stabilize.Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.Storm slabs are expected to be most sensitive to triggering in wind exposed terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Valid until: Mar 23rd, 2018 2:00PM