Avalanche Forecast

Issued: Mar 2nd, 2022 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

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Danger is declining as the weather clears and cools, but there is uncertainty about how quickly layers in the upper snowpack will strengthen. Evaluate snow and terrain carefully.

Summary

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

WEDNESDAY NIGHT: Mostly cloudy skies with some convective flurries bringing trace amounts of snow, light wind from the southwest, treeline temperatures drop to -6 C.

THURSDAY: Mostly cloudy skies with isolated flurries bringing up to 5 cm of snow, light wind from the southwest, treeline temperatures reach -3 C with freezing level climbing to 1500 m.

FRIDAY: Mostly sunny, light wind from the northeast, treeline temperatures around -5 C.

SATURDAY: Sunny, light wind from the northeast, treeline temperatures around -5 C.

Avalanche Summary

Widespread storm slab avalanche activity was observed on Monday and Tuesday. The storm slabs were very reactive to skiers, producing size 1-1.5 avalanches on convex rolls. These avalanches ran on recently buried crust and surface hoar layers, roughly 20 to 40 cm deep. Larger (size 2-2.5) natural avalanches were observed on bigger alpine slopes, and wet loose avalanches occurred at lower elevations. The reactivity of the storm slabs is likely diminishing rapidly, although the potential to trigger them exists on some slopes.

Over the past two weeks we have seen sporadic large (size 2 to 3) persistent slab avalanches on buried surface hoar and crust layers. Most of the activity has been in the Valhalla, Goat, and Kokanee Ranges. Recent weather trends have likely helped stabilize these layers, but we aren't quite ready to rule out the possibility of large persistent slab avalanches in parts of the region.

Snowpack Summary

Recent storm snow has likely settled into 20 to 40 cm of heavy powder at upper elevations and wet/crusty snow below 2000 m. Reactive slabs may still be found on wind loaded slopes and perhaps some isolated areas where this snow sits above sun crusts or feathery surface hoar. The recent storm delivered more snow to the Selkirks than the Monashees. The snowpack is generally well settled below the new snow, although there are two potential weak layers buried 50 to 100 cm deep. They both consist of surface hoar and/or melt-freeze crusts. Recent trends suggest these layers have been more reactive in southern parts of the region around the Valhallas, Kokanee, and Goat Ranges. We are uncertain about the reactivity of these layers after the recent storm.

Terrain and Travel

  • If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.
  • Be carefull around freshly wind loaded features.
  • Investigate the bond of the recent snow before committing to your line.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.

Problems

Storm Slabs

An icon showing Storm Slabs

20 to 40 cm of recent storm snow will bond relatively quickly in most areas, but may still produce avalanches in specific terrain features. This includes wind loaded slopes and open convexities at treeline where it may sit above sun crusts or feathery surface hoar.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

Persistent weak layers have gained strength over the past week, but it may still be possible to trigger large avalanches on buried surface hoar or crust layers found 50 to 100 cm deep. The problem is most likely found in the southern part of the Selkirk range (e.g. Valhalla, Goat and Kokanee ranges), especially on open convex slopes.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Mar 3rd, 2022 4:00PM