Avalanche Forecast

Issued: Mar 5th, 2019 4:20PM

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

mconlan, Avalanche Canada

Kootenay Boundary.

Wind slabs may be reactive in the alpine. The persistent slab problem still exists at lower elevations and is best controlled by diligent group management and terrain travel.

Summary

Confidence

High -

Weather Forecast

TUESDAY NIGHT: Increasing clouds, moderate southeast wind, alpine temperature -7 C.WEDNESDAY: Cloudy with light snowfall, trace accumulation, light to moderate southeast wind, alpine temperature -9 C.THURSDAY: Cloudy with snowfall, accumulation 10 cm, moderate southwest wind, alpine temperature -10 C.FRIDAY: Cloudy with light snowfall, accumulation 1 to 3 cm, light to moderate northwest wind, alpine temperature -10 C.

Avalanche Summary

Small (size 1) wind slab avalanches were reported on Monday, being triggered by skiers.Also on Monday, a small (size 1) persistent slab avalanche was triggered by a skier. It released on the mid-February layer described in the Snowpack Summary. It was between 20 and 50 cm deep, on a south aspect, and at 2100 m. Similar avalanches have been triggered recently, such as this one.

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. A melt-freeze crust likely prevails on southerly slopes.Two layers of weak and feathery surface hoar crystals are buried in the snowpack between 40 and 80 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 over the past week.

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.

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

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

Two layers of weak surface hoar and/or a crust are buried 40 to 80 cm. These layers have recently been the most active between 1700 m and 2200 m and on southwest to southeast aspects. The problem is best controlled with appropriate group management.

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

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Unlikely

Expected Size

1 - 2

Valid until: Mar 6th, 2019 2:00PM