Avalanche Forecast

Issued: Mar 31st, 2018 3:47PM

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

Avalanche Canada simonhorton, Avalanche Canada

Fresh snow from the past week is capable of producing large avalanches, especially on wind-loaded terrain features.

Summary

Confidence

Moderate - on Sunday

Weather Forecast

SUNDAY: Flurries intensifying throughout the day with 5-10 cm of snow by the afternoon and then another 5-10 in the evening, moderate southwest wind, freezing level up to 1000 m, and alpine high temperatures near -6 C.MONDAY: Mostly cloudy with light wind, freezing level up to 800 m, and alpine high temperatures near -8 C.TUESDAY: Cloudy with isolated flurries, light wind, freezing level up to 1200 m, and alpine high temperatures near -5 C.

Avalanche Summary

Friday's storm caused a natural avalanche cycle with numerous size 1-2 avalanches in the top 20-30 cm of new snow. Storm slabs were also reactive to skiers, producing several size 1 avalanches on small terrain features on various aspects.Storm slabs avalanches have been reported on a regular basis since Tuesday's storm. Natural avalanches up to size 3 were reported from Tuesday's storm on all aspects from 1900-2800 m. South and west aspects were the most reactive with slabs running on the recently buried late-March crust. In the days following the storm, several size 2 skier and remotely (from a distance) triggered storm slab avalanches were reported. On Wednesday, most human-triggered avalanches were on south and west aspects in the alpine, while activity on Thursday was mostly on east aspects at treeline. Skier triggered slabs were mostly 30-50 cm thick and ran on the late-March layer.

Snowpack Summary

Another 20-30 cm of snow on Friday brings the weekly total throughout the region to 40-80 cm. Strong west winds have redistributed the snow in alpine and treeline terrain.The storm snow sits on an interface buried in late-March that consist of crusts below 1900 m and on south aspects, and surface hoar on shaded aspects at higher elevations.A deeper layer buried mid-March is now 60 to 90 cm below the surface, and is similar to the late-March interface.Deeper persistent weak layers from January and December are still being reported by professional observers, but are generally considered dormant.

Problems

Storm Slabs

An icon showing Storm Slabs
Human-triggered storm slabs remain a concern in many areas. Wind-affected features on north and east aspects are suspect, as are steep south aspects where storm slabs may sit above buried sun crusts.
Be careful with wind loaded and cross-loaded slopes, especially near ridge crests and roll-overs.Choose well supported terrain without convexities.Minimize exposure to steep planar south-facing slopes

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Valid until: Apr 1st, 2018 2:00PM