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
Weather Forecast
A high pressure system brings clear skies and a diurnal melt-freeze cycle.
SUNDAY NIGHT: Clearing skies, 30-40 km/h northeast wind, freezing level drops to valley bottom with treeline temperatures dropping to -6 C.
MONDAY: Mostly sunny, light northeast wind, freezing level climbs to 1900 m with treeline temperatures reaching -1 C.
TUESDAY: Sunny, light wind, freezing level climbs to 2100 m with treeline temperatures reaching +1 C.
WEDNESDAY: Sunny with some afternoon clouds, light west wind, freezing level climbs to 2400 m with treeline temperatures around +4 C.
Avalanche Summary
Reports are relatively limited but there has been evidence of widespread size 1-2 wet loose avalanches on sun-exposed slopes since the warm weather arrived last week. There have also been a few large (size 2.5-3.5) wet slab avalanches reported in Glacier National Park (on Thursday, Friday and Saturday). A few recent natural cornice failures of size 2.5 did not trigger slabs on slopes below. Several glide cracks opened up and glide snow avalanches released with the warm temperatures. Glide slabs are hard to predict and can release at any time, so it is important to avoid slopes with glide cracks.
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 2200 m. There are no layers of concern in the snowpack, which has been melting and settling over the past week. Large cornices loom along many ridgelines.
Terrain and Travel
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
- 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
