Kootenay Boundary Avalanche Forecast

Issued: Mar 1st, 2021 4:00PM

Tue Mar 2nd Current Conditions
Alpine Moderate Treeline Moderate Below Treeline Low
Wed Mar 3rd 2 Day Outlook
Alpine Considerable Treeline Considerable Below Treeline Considerable
Thu Mar 4th 3 Day Outlook
Alpine Considerable Treeline Considerable Below Treeline Considerable

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

Potential for human triggering may remain in wind loaded pockets and steep openings in the trees where surface hoar may be buried. Be ready to back off your line if the sun comes out long enough to fry the snow - it can really pack a punch at this time of year.

Summary

Confidence

Moderate -

Weather Forecast

Monday night: Flurries bringing a few cm's. Freezing level dropping to 700 m. Strong southwesterly wind above 2000 m.

Tuesday: Mix of sun and cloud with isolated flurries. Freezing level 1500 m. Strong southwesterly wind above 2000 m, easing to moderate in the afternoon.

Wednesday: Sunny. Freezing level 2000 m. Light to moderate southwest wind.

Thursday: Sunny. Freezing level 2300 m. Light to moderate southwest wind.

Avalanche Summary

Over the weekend, there were a few natural and skier triggered wind slabs size 1.5, along with reports of wind slabs being stubborn to ski cuts. On Saturday, large explosive loads produced size 2-3 results at Kootenay Pass. In thin snowpack areas on solar aspects, a few of these large avalanches are suspected to have stepped down to the January layer described in the snowpack summary.

Snowpack Summary

At upper elevations, 20-40 cm of recent snow has seen significant wind effect, with reports of cross-loaded features and scouring on exposed windward aspects. Around treeline and below, the recent snow may sit over a layer of small surface hoar crystals in isolated areas.

A persistent layer buried 80-150 cm deep is composed of combinations of surface hoar, crusts and facets formed on the surface in late January. Very large loads are required to trigger an avalanche on this layer, but when triggered, large, destructive avalanches result. Examples of large triggers include large explosives, an avalanche in motion, cornice fall, or even a rapid rise in temperature such as the one forecast later this week. 

Shallow snowpack areas in the east of the region may harbor a facetted basal snowpack as described in this MIN report. This structure is often a constant for thin snowpacks and can be managed with good travel habits of avoiding shallow rocky areas where the snowpack transitions from thick to thin.

Terrain and Travel

  • Be careful as you transition into wind affected terrain.
  • Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
  • Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible

Expected Size

1 - 2

Wind slabs may be found on a variety of aspects. Recent wind direction has ranged from northwest to south.

Aspects:

North, North East, East, South East, North West.

Elevations:

Alpine, Treeline.

Valid until: Mar 2nd, 2021 4:00PM

Forecast Trend

The latest forecast danger ratings, broken down to elevation. See how an elevation is trending.