Avalanche Forecast
Issued: Mar 21st, 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.
ahanna,
Avalanche Canada
Avalanche danger will increase as new snow and wind form fresh wind slabs at upper elevations. Don't forget about a buried weak layer that remains triggerable around treeline.
Summary
Confidence
Weather Forecast
Monday night: Snowfall 5-10 cm. Strong southwest wind. Alpine temperature around -2 °C. Freezing level rising to 1500 m.
Tuesday: Snowfall 5-10 cm. Strong southwest wind. Alpine high around -1 °C. Freezing level 1700 m.
Wednesday: Overnight snowfall 5-10 cm then clearing. Moderate southwest wind. Alpine high around -6 °C. Freezing level 1000 m.
Thursday: A mix of sun and cloud. Moderate south wind. Alpine high around -5 °C. Freezing level 1200 m.
Avalanche Summary
On Sunday, natural cornice-triggered wind slab avalanches were reported up to size 2.
Persistent slab avalanches on a weak layer of surface hoar crystals buried in late February have surprised a few people in the last week with quickly propagating accidental and remote triggers. The layer has been most active on north-northeast aspects between 1200 and 1600 m in areas north of Hazelton.
Snowpack Summary
Strong winds have blown new and recent snow into wind slabs at upper elevations.
A few sun crust and surface hoar layers exist in the upper snowpack. The most concerning of which is a layer of surface hoar crystals found 30-45 cm deep. It has a tendency to surprise riders given it's spotty distribution, most often found on north to east aspects around treeline.
A thick crust formed in mid-February is now buried 50-80 cm deep. It is unlikely to present an avalanche problem under the current conditions and in fact bridges any underlying instabilities in the lower snowpack.
Terrain and Travel
- Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
- Dial back your terrain choices if you are seeing more than 20 cm of new snow.
- Be aware of the potential for large avalanches due to the presence of buried weak layers.
- Surface hoar distribution is highly variable. Avoid generalizing your observations.
- Caution around convexities or sharp changes in terrain.
Problems
Wind Slabs
New snow and wind are building fresh and reactive wind slabs in lee terrain features at upper elevations. Features where wind deposited snow tends to accumulate include just below ridge crests and roll overs and on the lee side of rib features.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A couple of layers of surface hoar exist in the upper snowpack, sometimes in combination with a crust. The problem and associated avalanche activity have been spotty both across terrain features and across the region. The best approach is to employ travel habits to manage it unless you can rule it out in your riding area.
Aspects: North, North East, East.
Elevations: Treeline.
Likelihood
Expected Size
Valid until: Mar 22nd, 2022 4:00PM
