Avalanche Forecast

Issued: Mar 4th, 2019 4:57PM

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

mconlan, Avalanche Canada

Kootenay Boundary.

Wind slabs continue to be reactive at higher elevations. A persistent slab problem still exists and has been responsible for sporadic human-triggered avalanches.

Summary

Confidence

High -

Weather Forecast

MONDAY NIGHT: Clear skies, moderate to strong east wind, alpine temperature -11 C.TUESDAY: Mostly clear skies, moderate southeast wind, alpine temperature -8 C.WEDNESDAY: Cloudy with light snowfall, accumulation 1 to 3 cm, light to moderate east wind, alpine temperature -8 C.THURSDAY: Cloudy with snowfall, accumulation 5 to 10 cm, moderate southwest wind, alpine temperature -10 C.

Avalanche Summary

Numerous small (size 1) wind slab avalanches were reported on Monday. They were triggered naturally and by skiers. They occurred on west to northwest aspects between 1800 and 2200 m and were 10 to 30 cm deep.Also on Monday, a large (size 2) persistent slab avalanche was triggered by a snow sluff caused by a vehicle. It released on the mid-February layer described in the Snowpack Summary. It was 35 cm deep, on a southeast aspect, and at 1900 m. A similar avalanche was triggered by a skier on Saturday; check it out here.

Snowpack Summary

Strong east wind has scoured the snow surface in exposed terrain and produced wind slabs in lee and cross-loaded terrain features. In sheltered areas, soft snow may still be found. On sunny slopes, you may find moist snow during the day or otherwise a frozen melt-freeze crust.Two layers of weak and feathery surface hoar crystals are buried in the snowpack between 30 and 60 cm deep, which were buried mid-February and early-February. The layers may be associated with a melt-freeze crust on southerly aspects. These layers remain reactive in snowpack tests and have produced sporadic avalanches in the region.

Problems

Wind Slabs

Continuing strong wind has produced touchy wind slabs in lee and cross-loaded terrain features. The most suspect slopes will be near ridges on south, west, and north aspects, as the wind has been blowing from the east.

Use caution in freshly wind-loaded features, especially near ridge crests and in steep terrain.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Keep an eye out for reverse loading created by wind from the east.

Aspects: North, South East, South, South West, West, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

It remains possible to trigger an avalanche on weak surface hoar and/or a crust buried 30 to 60 cm. These layers have recently been the most active at treeline elevations but may still exist below treeline.

Apply caution around sheltered and open areas at treeline and below. Space out to limit exposure.Choose moderate-angled terrain with low consequence, avoiding terrain traps.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2.5

Valid until: Mar 5th, 2019 2:00PM