Avoid north-facing alpine and treeline slopes, as this is where triggering persistent weak layers is most likely. Uncertainty is best managed through conservative terrain choices.
Previous southwesterly winds built wind slabs on leeward northerly and easterly slopes. If triggered, wind slab avalanches may step down to deeper layers, resulting in very large avalanches.
Weak layers formed in January persist within the upper 100 cm of snow. Avoid shallow snowpack areas where triggering these layers is more likely. In times of uncertainty, conservative terrain choices are our best defense.
Over the weekend, numerous natural and human-triggered avalanches, up to size 3, were reported at all elevations and aspects, many failing on the late January persistent weak layer.
On Saturday, a skier remotely triggered a size 3 persistent slab avalanche on a northwest-facing slope at 2050 m. See MIN for photos and details.
Natural avalanche activity has tapered off with cooler temperatures; however, human triggering the persistent layers remains a concern.
By Wednesday morning, a few centimeters of snow covers a melt-freeze crust that extends to ridgetops on all aspects, except northerly slopes above 1700 m, where surfaces remained dry through the warm-up.
A weak layer formed in February, consisting of facets, surface hoar, or a crust, is found 30 to 60 cm deep. Additional weak layers formed in January are present at varying depths within the upper 100 cm of snow, including faceted snow, crusts on south-facing slopes, and surface hoar in shaded terrain.
The mid and lower snowpack is generally well-settled and strong.
Tuesday Night
Cloudy with light flurries, 1 to 2 cm of snow. 10 to 25 km/h southwest ridgetop wind. Treeline temperature -7 °C. Freezing level 1000 m.
Wednesday
Cloudy with light flurries, 1 to 3 cm of snow. 10 to 20 km/h northwest ridgetop wind. Treeline temperature -6 °C. Freezing level 1300 m.
Thursday
A mix of sun and cloud. 10 to 25 km/h northwest ridgetop wind. Treeline temperature -4 °C. Freezing level 1500 m.
Friday
A mix of sun and cloud. 30 to 40 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1600 m.
More details can be found in the Mountain Weather Forecast.
