Surprising skier-triggered avalanches, including some step-down, are evidence of reactive persistent slabs. Keep choosing low-consequence slopes with no overhead hazard.
Persistent weak layers including crust/facet combos and buried surface hoar continue producing surprising avalanches. Be aware of the potential for wide propagation, especially at treeline.
Ongoing snowfalls and winds will continue to create reactive storm slabs. The largest and most reactive are expected to be on northerly aspects. Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Large and very large slabs and accidentally triggered avalanches continue to occur across the region. On Monday, numerous surprising avalanches were skier-triggered at treeline, including a step-down. Some have been triggered from low-angle terrain onto adjacent slopes. We expect the potential for riders to trigger avalanches will remain elevated over the following days.
For more information, click on the photos below.
Recent storm snow, now totalizing 40 to 80 cm, has formed reactive slabs across the region. Several persistent weak layers are now buried between 80 and 160 cm deep, including hard crusts with overlying weak facets and surface hoar. These weak layers have been responsible for continued avalanche activities over the last week.
At lower elevations, the upper snowpack may be moist or crusty.
Tuesday Night
Cloudy with 2 of new snow expected. 30 to 40 km/h south ridgetop wind. Treeline temperatures around 0 °C. Freezing level returning to valley bottom.
Wednesday
Cloudy with 3 to 5 cm of new snow expected. 50 to 70 km/h southwest ridgetop wind. Treeline temperatures around 0 °C. Freezing level rising to 1200 m.
Thursday
Cloudy with 10-20 cm of new snow expected. 60 to 80 km/h southwest ridgetop wind. Treeline temperatures around +3 °C. Freezing level rising to 1500 m.
Friday
Cloudy with no precipitation. 40 to 60 km/h southwest ridgetop wind. Treeline temperatures around +5 °C. Freezing level rising to 2500 m.
More details can be found in the Mountain Weather Forecast.
