Avalanche Forecast
Issued: Mar 20th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
wlewis,
Avalanche Canada
Watch for reactivity on specific features - buried layers of surface hoar and crust are still surprising backcountry users.
Understand how avalanche danger may change as you move through different aspects and elevations before planning your trip.
Summary
Confidence
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
SUNDAY: Light to moderate westerly winds. Scattered flurries. Freezing levels drop to valley bottom.
MONDAY: Flurries possible with light southwest winds. Mostly cloudy. Freezing levels rise to 1500 m. Alpine high of -1.
TUESDAY: Freezing levels only push higher, reaching near 2500 m. A mix of sun and cloud. Moderate southwest winds. Alpine high +4.Â
WEDNESDAY: Around 5 cmm forecast, as freezing levels sit above 1800 m for most of the day.Â
Avalanche Summary
Overall reports indicate a gradual tapering of reactivity of the buried weak layers, however reactivity remains in specific features where these weak layers are more prominent.Â
Several size 2 slab avalanches were reported on Saturday, from natural and human triggeres. Activity mostly occurred on north facing slopes at treeline, indicating the continued reactivity of the buried surface hoar.
The crust on south facing aspects has shown reactivity within the last 3 days, producing natural and human triggered avalanches to size 2.Â
Loose wet avalanches have been reported at elevations below the freezing line, and on sun affected slopes over the past 5 days.Â
Snowpack Summary
Up to 60 cm of recent settling storm snow sits over a layer of weak surface hoar in sheltered and shaded terrain, and over a crust on south facing slopes. Test results show that the new snow is bonding poorly to old surfaces in many areas, producing large avalanches within the last 3 days and reactive results to tests.Â
At higher elevations consistent southwest winds are creating deeper deposits on north through east facing features. Below 1500 m, moist snow or a melt-freeze crust likely exists from recent rain and warm temperatures.
The late February persistent weak layer combination of crust, facets and surface hoar is down 70-90 cm. Two persistent weak layers from mid-February and late January are buried 100-170cm deep. Avalanches on these layers are unlikely to be triggered.
Terrain and Travel
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
Problems
Persistent Slabs
A buried crust on south facing slopes continues to be sensitive to human triggering, producing large avalanches within the last 3 days. Short periods of sunshine may increase likelihood of triggering on south facing features.
A spotty layer of surface hoar buried on sheltered and shaded terrain features at treeline has also shown recent reactivity.
Most reactivity has been seen around Malakwa (Queest/Gorge area), Highway 23 North (Downie Creek and Goldstream FSR areas) and terrain surrounding Valemount and Blue River.
More information can be found here in the new forecaster blog.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Expect freshly wind loaded features to be reactive to human triggers as southwest winds continue.
Be aware that small avalanches in motion may step down to deeper layers.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 21st, 2022 4:00PM
