Avalanche Forecast

Issued: Mar 1st, 2019 4:28PM

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.

swerner, Avalanche Canada

Kootenay Boundary.

Wind slabs continue to be reactive to human triggers, especially on south-southwesterly aspects at treeline and above.

Summary

Confidence

High - The weather pattern is stable

Weather Forecast

Heading into March it feels more like January. The strengthening ridge will bring us another fairly long stretch of cold, dry and clear weather.SATURDAY/ SUNDAY/ MONDAY: Mostly sunny with treeline temperatures near -15. Moderate ridgetop wind from the East through the forecast period.

Avalanche Summary

On Thursday, dry loose sluffing was seen in steeper terrain features.

Snowpack Summary

An additional 15 cm accompanied by light southwest winds fell in Kootenay Pass and the Nelson area overnight. This adds an additional 20-30 cm of low density snow to the upper snowpack. This new snow may have a poor bond to the previous firm and faceted (sugary) snow surfaces. Old wind slabs from the strong northeast winds earlier this week continue to reactive to human triggers especially on southerly slopes. A buried surface hoar and crust interface that was buried on February 7th is now 30-50 cm deep. Two other surface hoar layers are buried 50 to 80 cm deep the snowpack (referred to as the February 1st and mid-January layers) these buried persistent weak layers remain reactive to human triggers. The snowpack is complex and requires diligence and patience. This MIN report reflects the Kootenay Pass area well. This MIN report reflects the Bonnigton Range.

Problems

Wind Slabs

Wind slabs likely exist on all aspects due to changing winds. Southerly slopes and terrain features have been most reactive. Loose dry sluffing may exist on steep slopes and terrain features with the recent snow.

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: All aspects.

Elevations: All elevations.

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 30 to 80 cm deep. These layers are most prominent around treeline elevations.

Caution around sheltered open areas at treeline and below including cutblocks, gulleys, and glades.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Use increased caution on open slopes and convex rolls at lower elevations.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Mar 2nd, 2019 2:00PM