Avalanche Forecast

Issued: Mar 29th, 2014 10:17AM

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

ghelgeson, Avalanche Canada

Northwest Inland.

Summary

Confidence

Fair - Wind effect is extremely variable

Weather Forecast

Synopsis: A ridge of high pressure over the NWT and little to no flow aloft will lead to a continuation of cold and dry conditions over the North Coast.Sunday: Freezing Level: 700m - 900m; Precipitation: Nil; Wind: Treeline: Light, SE | Ridgetop: Light, NMonday: Freezing Level: 1300 - 1600m; Precipitation: Nil; Wind: Treeline: Light, NW | Ridgetop: Light, NWTuesday: Freezing Level: 1200 - 1700m Precipitation: Nil; Wind: Treeline: Light, SW | Ridgetop: Moderate, NW

Avalanche Summary

On Friday a skier remote triggered a size 1 wind slab on a southwest facing feature at 1500m. Loose snow avalanches to size 2 were running in the recent storm snow on both SW and NE facing slopes Thursday. One fresh wind slab on a NE facing feature at 1700m was also reported. We received a report of a skier triggered avalanche in the Kispiox range that occurred on Wednesday. The size 2 avalanche caught and carried a skier on an alpine feature, thankfully the skier walked away from the incident. Sounds like it ran on the March crust/facet/surface hoar interface.

Snowpack Summary

The recent storm snow (40-50 cm) has been transported into pockets of wind slab by moderate Southwest winds in the South of the region and by Easterly winds in the North of the region. The storm slab is sitting on the March persistent weak layer of crusts/facets/surface hoar that is widespread across the region. A late January/early February crust/facet/surface hoar combo is still showing up in snowpack tests with moderate to hard shear test results. This layer is expected to be with us for a long time, and a slide triggered on this layer could be very large and destructive.

Problems

Wind Slabs

Easterly winds have developed wind slabs on lee aspects. Some areas in the South of the region may have had periods of Southwest winds.

Travel on ridgetops to avoid wind slabs on slopes below.>Avoid freshly wind loaded features.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 4

Persistent Slabs

The recent storm snow may not be well bonded to the buried weak layer of crusts/facets/surface hoar that developed during early March. Forecast cool temperatures may help to preserve this weak layer.

Be aware of the potential for large, deep avalanches due to the presence of buried weak layers>Be aware of thin areas that may propogate to deeper instabilites.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 4

Deep Persistent Slabs

The deeply buried persistent weak layer from early February continues to be a concern. Heavy loads like cornice falls or storm slab avalanches in motion may trigger this weak layer resulting in very large and destructive avalanches.

Pay attention to overhead hazards like cornices.>Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

4 - 7

Valid until: Mar 30th, 2014 2:00PM