Avalanche Forecast

Issued: Mar 23rd, 2015 9:50AM

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

Avalanche Canada ghelgeson, Avalanche Canada

Touchy conditions exist in the North of the region with the potential for large and destructive avalanches.

Summary

Confidence

Fair

Weather Forecast

Monday Night: Convective precipitation amounts are hard to pin down. The region could see 5cm to as much as 15cm above 1000m with very little wind.Tuesday: Scattered convective flurries. Freezing level rising to 1700m in the late afternoon. Light NW winds at all elevations.Wednesday: Winds out of the SW begin to pick up as warm air floods into the region. Look for light SW winds at treeline, potentially strong SW winds at ridgetop. Freezing level should climb to 2000m by late afternoon. 2 to 4mm of rain possible.Thursday: 1 to 5mm of rain. Light SW winds at treeline, strong W/SW winds at ridgetop. Freezing level starting the day at 2000m, climbing to 3000m by the afternoon.

Avalanche Summary

Over the past week, there have been a number of avalanches to size 2.5 occurring on the March 11 persistent weak layer. Some avalanches have occurred naturally, or remotely from distances of up to 100m. Hot spots for avalanche activity seem to include the Duffey Lake area, the Birkenhead drainage, the Hurley and the South Chilcotins. Snow and wind on Monday night will likely add a round of wind slab activity to the mix. But it will also add load to the March layer, potentially adding to its reactivity and destructive potential.

Snowpack Summary

New wind slabs have formed in response to recent wind, snowfall and warm temperatures. At lower elevations, rain has saturated the snowpack. Cornices may also be fragile. A touchy crust/facet persistent weak layer, buried up to 60 cm down, has been reactive producing easy test results at upper treeline and alpine elevations, especially in the north of the region (see avalanche summary). Avalanche problems associated with this layer may linger for a while with the potential for surprisingly large and destructive avalanches. Below this, the snowpack is reported to be generally well-settled and strong.

Problems

Persistent Slabs

An icon showing Persistent Slabs
Easy failures in snowpack tests and large natural avalanches show that a recently buried crust/facet layer commands respect. Touchy conditions are expected to persist for the foreseeable future, especially in the north of the region.
Remote triggering is a concern, watch out for adjacent slopes.>Avoid steep high consequence features, convexities and areas with a thin or variable snowpack.>Pay attention to overhead hazards.>Choose conservative lines and watch for clues of instability.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 4

Storm Slabs

An icon showing Storm Slabs
New snow Monday night may create fresh storm slabs in high elevation terrain. Due to the convective nature of the system, "power flurries" may occur resulting in higher accumulations than anticipated.
The new snow will likely require a day to settle and stabilize.>Storm snow in motion could initiate an avalanche failing on the mid-march persistent weak layer.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Mar 24th, 2015 2:00PM