Wet loose avalanches become increasingly likely during the heat of the day. Back off slopes as the surface becomes moist or wet with daytime warming and avoid slopes with large cornices overhead.
Summary
Confidence
Weather Forecast
WEDNESDAY NIGHT: Clear / Light, northwest ridgetop wind / alpine low temperature -4 / Freezing level 1400 m.
THURSDAY: Sunny / Moderate, northwest ridgetop wind / alpine high temperature 5 / Freezing level 1600 m.
FRIDAY: Mix of sun and cloud / Light, northwest ridgetop wind / alpine high temperature 5 / Freezing level 1500 m.
SATURDAY: Sunny / Light, southeast ridgetop wind / alpine high temperature 3 / Freezing level 1300 m.
Avalanche Summary
Numerous naturally triggered wet loose avalanches to size 2.5 were reported on Tuesday. Additionally, numerous cornice failures were reported, but they were not triggering slab avalanches on the slopes below.
Numerous large to very large (size 2-3) natural and explosive-triggered wet loose and wet slab avalanches were reported over the weekend at all elevations. A couple of natural cornice failures on northeast alpine slopes triggered very large (size 3) avalanches on slopes below.
Snowpack Summary
The snowpack has been undergoing a melt-freeze cycle with successive days of warm sunny weather. Strong solar radiation and warming will likely initiate wet loose avalanches as the snow loses cohesion. As the heat penetrates deeper into the snowpack, operators have reported larger wet slab avalanches. These avalanches are dense, destructive, and can run far, reaching otherwise snow-free valley bottoms. Cornices are large and looming along ridgelines. Sun and warm temperatures will increase the chances of cornice failures, especially when temperatures remain above zero overnight. Check out the Forecaster's Blog for information on how to manage these spring conditions.
The snowpack is overall strong and settled in most areas, however, sustained warming can increase the likelihood of large avalanches failing on deeply buried weak layers. This is most likely to occur on steep, rocky alpine slopes with a shallow or thin to thick snowpack.
Glide cracks releasing as full depth glide slab avalanches become more common in the spring and are extremely difficult to predict. Best practice is to avoid slopes with glide cracks.
Terrain and Travel
- Avalanche hazard is expected to to increase througout the day, think carefully about your egress.
- Back off slopes as the surface becomes moist or wet with rising temperatures.
- As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
- Minimize overhead exposure; avalanches triggered by warming or cornice fall may be large and destructive.
Problems
Loose Wet
Wet loose avalanches become increasingly likely during the heat of the day.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Strong solar radiation and warming will likely trigger the large cornices that hang over ridge lines. Cornice falls are a hazard on their own, but could also trigger large avalanches on the slopes below.
Aspects: North, North East, East, West, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 22nd, 2021 4:00PM
