Avalanche Forecast
Issued: Mar 25th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
zryan,
Avalanche Canada
Wind slabs may be reactive to human triggering at upper elevations. Use caution in lee and cross-loaded terrain near ridge crests.
Summary
Confidence
High - The snowpack structure is generally well understood.
Weather Forecast
FRIDAY NIGHT: Cloudy with light snowfall, up to 5 cm accumulation. 15 to 35 km/h southwest wind, alpine temperature -3 C.
SATURDAY: Cloudy with light snowfall, up to 5 cm of accumulation, 15-30 km/h southwest winds, alpine temperature rising to -3 C. Freezing level reaching 1700 m.
SUNDAY: Cloudy with precipitation, 5-10 cm of new snow accumulation at higher elevations. 20-50 km/h southwest winds, alpine temperature rising to -3 C. Freezing level reaching 2400 m.Â
MONDAY: Cloudy with snowfall, 5-15 cm accumulation. 15-30 km/h northwest winds, alpine temperature rising to -3 C. Freezing level reaching 2000 m.
Avalanche Summary
Widespread loose wet and wet slab avalanche activity occurred during the warm-up on Wednesday.Â
Two persistent slab avalanches were reported on Thursday, both on south-facing alpine slopes. One was a large (size 2.5) natural avalanche and the other was a small (size 1.5) slab remotely triggered by riders.
Looking forward, riders may be able to trigger wind slabs in lee terrain features in steep alpine terrain. It also may be possible to trigger the weak layer described in the Snowpack Summary, where it still exists.
Snowpack Summary
Above 2000 m, 5 to 15 cm of recent snow and southwest winds may have formed small wind slabs in lee terrain features. Below 2000 m, up to 5 cm of new snow overlies a melt-freeze crust with moist snow below.
A weak layer may be found around 50 to 100 cm deep. The layer consists of surface hoar crystals in treeline terrain on northerly aspects or weak faceted grains above a hard melt-freeze crust on sun-exposed slopes (i.e., east, south, west). It has been reactive between 1800 and 2300 m but given the recent rain, it is most likely to be triggered between 2000 and 2300 m. It should still be treated as suspect if you find it in your riding area.
The remainder of the snowpack is well-bonded.
Terrain and Travel
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Carefully evaluate steep lines for wind slabs.
- When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Wind Slabs
Wind slabs may be found in steep, lee terrain features in the alpine.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Persistent Slabs
A weak layer may be found around 50 to 100 cm deep. The layer is most likely to be triggered between 2000 and 2300 m, on all aspects. The likelihood of triggering this layer is decreasing, but the consequence of doing so would be high.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 26th, 2022 4:00PM
