Avalanche Forecast

Issued: Mar 28th, 2018 4:55PM

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

Avalanche Canada jmcbride, Avalanche Canada

The recent storm snow is being re-distributed by winds at upper elevations.  Watch for freshly wind-loaded areas and pay attention to how the storm snow has bonded to the old crusts.

Summary

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

THURSDAY: Mostly cloudy. Ridge wind light to moderate, west. Alpine temperature near -6. Freezing level 700 m. Snow beginning late afternoon.FRIDAY: Flurries. Accumulation 10-20 cm. Ridge wind moderate to strong northwest. Alpine temperature near -6. Freezing level 1000 m.SATURDAY: Mix of sun and cloud. Ridge wind light, west. Alpine temperature near -6. Freezing level 1000 m.

Avalanche Summary

A widespread natural avalanche cycle to size 3 was reported on Tuesday on all aspects at tree line and in the alpine. Solar aspects however were the most reactive with numerous size 3 storm slabs running on the recently buried crust.Several skier triggered size 1-2 storm slabs were also report on east and southwest aspects at treeline and above.On Monday, backcountry skiers triggered a size 2 wind slab near the Asulkan cabin on a northeast aspect near 2050m. The slab's thickness varied from 40-60cm. See the MIN report for more details. Over the past weekend, we received reports of several wind slabs and storm slabs to size 2.5, mostly on northerly aspects above 2200m. Also on Saturday, a wet loose size 1.5 avalanche injured a skier in Glacier National Park on a west aspect near 2000m.

Snowpack Summary

Storm snow amounts following Tuesday's storm typically range from 40 to 50 cm and up to 70 cm in some areas. This snow has fallen with moderate to strong winds from the south / east switching to west and northwest. The recent storm snow sits a variety of old surfaces; crust on solar aspects and all aspects below 1900m, and surface hoar on high north and east aspects.A deeper crust/surface interface buried March 18th is now down about 60 to 80 cm and is similar to the old surface.Deeper persistent weak layers from January and December are generally considered dormant, but could wake up with a surface avalanche stepping down, large cornice fall, or a human trigger in a shallow or variable-depth snowpack area. These layers consist of sun crust, surface hoar and/or facets.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slabs are expected to remain touchy, especially in wind-loaded areas above treeline. South aspects has been especially reactive due the presence of a buried crust beneath the recent storm snow.
Be careful with wind loaded slopes, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Valid until: Mar 29th, 2018 2:00PM