Avalanche Forecast

Issued: Mar 3rd, 2019 4:09PM

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

mbender, Avalanche Canada

Kootenay Boundary.

Wind slabs continue to be reactive at upper elevations. A persistent slab problem still exists in the region and has been responsible for sporadic human triggered avalanches over the past week.

Summary

Confidence

High - The weather pattern is stable

Weather Forecast

MONDAY: Mainly sunny / light to moderate east wind / alpine temperature -12 CTUESDAY: A mix of sun and cloud / light to moderate southeast wind / alpine temperature -8 CWEDNESDAY: Mainly cloudy with scattered flurries / light to moderate southeast wind / alpine temperature -6 C

Avalanche Summary

There is an excellent MIN post describing a skier triggered size 1.5 persistent slab avalanche on Saturday. Click here to see it. Additionally on Saturday reports indicate a few size 1-1.5 wind slab avalanches on west aspects in the alpine and treeline. There were reports of several size 1-1.5 explosives triggered storm slab avalanches on Friday in the alpine and tree line on northerly aspects.

Snowpack Summary

The surface consists of 15-30 cm of low density recent new snow. This new snow is sitting on old wind slabs and faceted (sugary) snow. A layer of feathery surface hoar sitting on a crust that was buried on February 7th is now 30-50 cm deep. Two other surface hoar layers are buried 50 to 80 cm down (referred to as the February 1st and mid-January layers) remain reactive in snowpack tests.

Problems

Wind Slabs

Most recent wind slab formation is on south and west facing slopes, however wind slabs likely exist on all aspects due to changing winds.

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.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

It remains possible to trigger an avalanche on one of the surface hoar or crust layers buried 40 to 80 cm deep. These layers seem to be most prominent at treeline.

Caution around sheltered open areas treeline and below.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Mar 4th, 2019 2:00PM