Avalanche Forecast
Issued: Mar 1st, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
shorton,
Avalanche Canada
Conservative terrain selection is recommended as the storm snow needs more time to strengthen and there is uncertainty about buried weak layers in parts of the region.
Summary
Confidence
Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.
Weather Forecast
TUESDAY NIGHT: Cloudy with isolated flurries bringing trace amounts of snow, moderate wind from the southwest, treeline temperatures drop to -6 C.
WEDNESDAY: Mostly cloudy skies with some convective flurries bringing trace amounts of snow, light wind from the south with moderate gusts during flurries, treeline temperatures reach -2 C with freezing level reaching 1700 m.
THURSDAY: Cloudy with scattered flurries bringing 5 to 10 cm of snow, light wind from the northwest, treeline temperatures around -5 C.
FRIDAY: Mostly sunny, light wind from the northeast, treeline temperatures around -5 C.
Avalanche Summary
Storm slabs were reactive on Monday and preliminary reports from Tuesday suggest they were even more reactive. Reports from Monday included numerous small (size 1-1.5) human triggered avalanches at treeline elevations, but also a few larger (size 2) slabs on larger features. The avalanches were typically 20 to 40 cm thick, and many ran on recently buried crust and surface hoar layers.
Over the past week there have been regular reports of sporadic large (size 2 and 3) persistent slab avalanches in the Valhalla, Goat, and Kokanee Ranges. These avalanches occurred on 50 to 100 cm deep surface hoar and crust layers. While many of the reports have been on north and east facing slopes, they have occurred on all aspects. The weak layers associated with these avalanches are currently being stressed by warming and the weight of the new snow.
Snowpack Summary
Recent storm snow has likely settled into 20 to 35 cm of heavy powder at upper elevations and wet/crusty snow below 2000 m. Reactive slabs are likely found on wind loaded slopes and perhaps some isolated areas where this snow sits above sun crusts or feathery surface hoar.Â
Two potential weak layers exist within the upper snowpack: the mid-February layer (down 40 to 60 cm) and the late-January layer (down 100 cm). They both consist of surface hoar and/or melt-freeze crusts. Recent trends suggest these layers have been most reactive in southern parts of the region around the Valhallas, Kokanee, and Goat Ranges. See photos of these layers from our forecasters' MIN report.
Terrain and Travel
- Choose slopes that are well supported and have limited consequence.
- Avoid freshly wind loaded terrain features.
- Caution around convexities or sharp changes in terrain.
- Approach steep, open and/or sparsely treed slopes cautiously.
Problems
Storm Slabs
Recent snow has settled into a 25 to 40 cm thick slab and can produce large avalanches. Terrain features of concern include wind loaded slopes in the alpine and at treeline, and open convexities at lower elevations where the new snow may sit above sun crusts or feathery surface hoar.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Persistent slab avalanches are possible due to two weak layers in the upper snowpack. This includes the mid-February layer (down 40 to 60 cm) and the late-January layer (down 100 cm), both consisting of surface hoar and/or melt-freeze crusts. With increased load from the current storm and warmer temperatures, they have the potential to "wake up" and produce large, unexpected avalanches. The greatest concern is in southern parts of the region where there has been more recent avalanche activity on these layers.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 2nd, 2022 4:00PM
