Warm temperatures and sunny skies increases the likelihood for large cornice failures and wet loose avalanches. Start early and plan to be off large slopes before the heat of the day.
Check out the latest Forecaster's Blog for more information on managing current conditions.
Summary
Confidence
Weather Forecast
FRIDAY NIGHT: Partly cloudy / Light, northwest ridgetop wind / alpine low temperature -1 / Freezing level 2000 m.
SATURDAY: Sunny / Moderate, northeast ridgetop wind / alpine high temperature 2 / Freezing level 1500 m.
SUNDAY: Sunny / Moderate, southeast ridgetop wind / alpine high temperature 5 / Freezing level rapidly rising to 2800 m.
MONDAY: Sunny / Light, southeast ridgetop wind / alpine high temperature 4 / Freezing level 2500 m.
Avalanche Summary
Several naturally triggered wet slab avalanches up to size 2.5 and numerous wet loose avalanches up to size 2 were reported on Thursday. See MIN.
Keep in mind that periods of rapid warming can weaken deeply buried weak layers and increase the likelihood of large natural avalanches.
Snowpack Summary
Lingering wind slabs may still be reactive in isolated areas on northerly aspects at upper elevations. All other terrain is undergoing a melt-freeze cycle with successive days of high freezing levels.
Strong solar radiation and warming often trigger wet loose avalanches and large cornice failures. Cornice falls could trigger large avalanches on deeply buried weak layers.
While there have not been many weak layers of concern this season, Keep in mind that periods of rapid warming can weaken deeply buried weak layers and increase the likelihood of large natural avalanches.This will more likely be an issue in shallow snowpack areas like the Wheaton compared to the thicker and stronger snowpack around White Pass.
Terrain and Travel
- Avoid travelling on slopes below cornices.
- The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
- Back off slopes as the surface becomes moist or wet with rising temperatures.
- If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Loose Wet
The snow surface will weaken over the course of the day as warm air and sunny skies prevail. The most likely areas to get into trouble are above terrain traps.
Warming could initiate slab activity in shallow snowpack areas like the Wheaton Valley.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Cornices are large and will weaken with daytime warming. Stay well back from them on ridges and avoid travelling beneath them. A cornice fall has the potential of triggering slabs on the slopes below.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 17th, 2021 4:00PM
