The best and safest riding will be high north-facing terrain that is free from cornices overhead. Expect avalanche activity on sun-exposed slopes.
Summary
Confidence
Moderate - Uncertainty is due to limitations in the field data.
Weather Forecast
A high pressure system brings clear skies and a diurnal melt-freeze cycle.
SUNDAY NIGHT: Clear skies, 30-40 km/h northeast wind, freezing level drops to valley bottom with treeline temperatures dropping to -8 C.
MONDAY: Sunny, light northeast wind, freezing level climbs to 2000 m with treeline temperatures reaching -1 C.
TUESDAY: Sunny, light wind, freezing level climbs to 2200 m with treeline temperatures reaching +1 C.
WEDNESDAY: Sunny with some afternoon clouds, light west wind, freezing level climbs to 2200 m with treeline temperatures around +2 C.
Avalanche Summary
There were reports of widespread size 1-3 wet loose avalanches on sun-exposed slopes on Thursday and Friday (see this MIN report). We have reports of some size 1 wet loose avalanches on Saturday, and suspect more natural wet avalanche activity happened throughout the region over the weekend. Several cornices failed recently. Most did not trigger slabs on slopes below except for a few that triggered size 2 slabs on extreme north facing alpine slopes.
With relatively cooler temperatures on Monday the likelihood of wet avalanches will be reduced, but they will still be possible on sun-exposed slopes.
Snowpack Summary
The snow surface consists of a melt-freeze crust on solar aspects and shaded aspects into the lower alpine, which transitions into moist/wet snow during the day. Dry snow might still be found on northerly aspects in the alpine above roughly 2200 m. While there have been no recent avalanches on buried weak layers, there are a few layers that could potentially be triggered with intense warming or a heavy cornice fall. This includes a few crusts buried over the last month as well as a 150 cm deep facet layer from the mid-February cold snap.
Terrain and Travel
- Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
- Minimize your exposure time below cornices.
- Avoid lingering or regrouping in runout zones.
Problems
Loose Wet
Expect wet loose avalanches to run naturally when steep slopes are exposed to the sun. Activity will start on east-facing slopes in the morning, south-facing slopes throughout the day, and continue on west-facing slopes into the evening.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices are large and fragile when exposed to the sun. Cornice falls are dangerous on their own and can possibly trigger avalanches on slopes below.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 19th, 2021 4:00PM
