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
Weather Forecast
SUNDAY NIGHT: Scattered flurries. Light to moderate westerly winds. Freezing levels drop to valley bottom.
MONDAY: Mostly cloudy with flurries, and light to moderate southwest winds. Freezing levels reach 1600 m, with alpine highs of 0.
TUESDAY: Freezing levels only push higher, potentially reaching 3000 m. A mix of sun and cloud. Light to moderate southwest winds, alpine high of +4.
WEDNESDAY: Freezing levels drop to around 2000 m over the day. Moderate to strong southwesterly winds. Alpine high of
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.
On Saturday numerous size 2 slab avalanches were human and naturally triggered. Avalanches varied from failing on recent storm snow interfaces to failing on the buried weak layers of concern. Activity mainly occurred at treeline elevations on northwest to south facing slopes.
Loose wet avalanches were noted in some areas where freezing levels rose significantly or where strong sunshine affected the snowpack.
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 on testing.
At higher elevations consistent southwest winds are creating deeper deposits on north through east facing features. Below 1700 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.
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- 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.
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
