Avalanche Forecast
Issued: Mar 17th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
JSmith,
Avalanche Canada
Southwesterly winds continue to form wind slabs on lee and cross-loaded terrain features. Use caution when transitioning into wind affected terrain and avoid wind loaded slopes below ridgetops.
Summary
Confidence
Weather Forecast
WEDNESDAY NIGHT: Snow; 5-10 cm. / Strong, southwest ridgetop wind / alpine low temperature -15 / Freezing level valley bottom.
THURSDAY: Mix of sun and cloud with isolated flurries; 0-3 cm. / Moderate, west ridgetop wind / alpine high temperature -11 / Freezing level valley bottom.
FRIDAY: Cloudy with flurries; 3-5 cm. / Light, northwest ridgetop wind / alpine high temperature -12 / Freezing level valley bottom.
SATURDAY: Sunny / Light, southwest ridgetop wind / alpine high temperature -14 / Freezing level valley bottom.
Avalanche Summary
On Sunday, numerous 40-60 cm. deep skier and sledder triggered wind slab avalanches up to size 2 were reported as failing on weak facets in the alpine and feathery surface hoar at treeline.
In some areas, the snowpack is currently more complex and variable than is normal for this region. This means the hard wind slabs may remain reactive to human triggers much longer than is normal in places where they are sitting on a persistent weak layer of facets or surface hoar and will be stubborn to trigger in areas where these layers are not present. See MIN HERE.
Snowpack Summary
Light amounts of snow and strong southwest winds continue to from fresh wind slabs on lee and cross-loaded features in the alpine.
The snowpack inland (between Wheaton and White Pass) is currently complex due to variability. A weak layer of buried (feather-like crystals) surface hoar has been seen in glades and gullies that are sheltered from the wind and buried 40-60 cm down. Whumps and cracking have been felt and seen beneath the skis. In other locations, a stiff slab sits above weak (sugary) faceted crystals, while some locations are showing a bomber snowpack, suggesting a high degree of spatial variability.
The Wheaton's continental snowpack is dominated by hard wind slabs overlying sugary facets and depth hoar. It's an untrustworthy snowpack structure that requires really good terrain selection and travel habits, or a healthy dose of luck.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Avoid lee and cross-loaded terrain.
- Caution around slopes that are exposed to cornices overhead.
Problems
Wind Slabs
Light amounts of snow and strong southwest winds continue to from fresh wind slabs on lee and cross-loaded features.
Wind slabs formed from previous north winds may still be reactive to human triggers where they are sitting on persistent weak layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 19th, 2021 4:00PM
