Avalanche forecast

Kootenay Boundary

Mar 1 – 2, 2023Avalanche Canada
View on map
Archived · expired 4 years ago

Avalanche danger

Fri
Sat
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
Open full map

Highlights

Low density snow has made for great riding conditions, but the storm snow still shows limited bonding with the old snow surface.

Be cautious around wind loaded features, and avoid confined terrain where sluff could sweep you off your feet.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2.5

    Low density storm snow is expected to remain reactive to human triggers. It sits over dense wind affected surfaces and a small surface hoar layer and will take time to gain strength and bond. Expect greater slab quality and propagation in wind affected features where snow is more cohesive.

    A layer of buried surface hoar or a sun crust may increase reactivity and produce larger avalanches than you expect. Reports suggest this is most prominent in the northern areas of the region around the Norns Range.

Confidence

Moderate

Avalanche Summary

This storm has produced avalanche activity to size 2.5 from natural and rider triggers, and explosive control methods. Most avalanches have occurred within the storm snow or on the old snow surface, while a few failed on the buried weak layers. Notably a size 2 slab avalanche occurred on the January 17th sun crust, 50 cm deep on a southwest aspect.

Avalanche activity is expected to taper off gradually as the storm snow begins to settle and bond.

Snowpack Summary

Storm totals average 30-50 cm of low density snow. Expect deeper deposits on north and east facing slopes, from southwest winds. In steep and sheltered terrain the low density snow has minimal slab quality and reacts as loose dry sluffing. Storm snow sits over heavily wind affected surfaces at all elevations and so far has not bonded well.

A layer of surface hoar can be found on shaded slopes, and a sun crust on sun affected slopes buried 30-60 cm deep. This interface has been noted as a failure plane for some avalanche activity.

Otherwise, the snowpack is generally well consolidated and bonding. The lower snowpack includes a layer of weak sugary crystals near the ground. These facets are slowly gaining strength and have not produced recent avalanche activity. We continue to track the layer and watch for any signs that it could wake up and produce very large avalanches.

Weather Summary

Tuesday Night

Snowfall tapers off early evening. Kootenay Pass and terrain near the US Border may see around 10 cm of low density snow. Light southerly winds switch norwest. Freezing levels at valley bottom, alpine high of -5 °C.

Wednesday

Mostly sunny with some cloud. Moderate westerly winds. Alpine high of -3 °C. Freezing levels reach 1000 m. No snowfall expected.

Thursday

Cloudy with light snowfall beginning early morning and continuing throughout the day, up to 15 cm is possible. Moderate to strong southwest winds. Freezing levels reach 1000 m, with an alpine high of -3.

Friday

Mix of sun and cloud with moderate westerly winds. Freezing level around 1000 m. Isolated flurries are possible.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.
  • Be especially cautious as you transition into wind affected terrain.

Regions covered