Avalanche Forecast

Poor - Due to the number of field observations

Lingering cloud may persist on Monday, but a general clearing trend is expected for the forecast period as a cool ridge of high pressure sets up over the region. Ridgetop winds should remain northerly, peaking on Monday at about 80kmh, then decreasing somewhat on Tuesday and Wednesday. Ridgetop temperatures should remain between -12 and -17 for all three days.

In the north of the region on Saturday, explosives avalanche control produced several wind slab avalanches up to size 2.5 on north and east facing terrain above 1400m. At least one of the avalanches stepped down to a crust/facet interface 100cm below the surface. The newly formed storm slab may remain ripe for human triggering for the next few days, especially in areas where persistent weak layers exist.

Reactive wind slabs have likely formed throughout the region in response to Friday and Saturday's snowfall, warm temperatures and extreme westerly winds. At lower elevations, precipitation fell as rain and the surface now exists as a refrozen crust. The new wind slabs are likely most destructive in the north of the region where storm accumulations totaled around 30cm and ridgetop wind speeds peaked at 130 kmh. The reactivity of these new wind slabs will likely change with elevation and underlying snowpack structure. Due to limited observations, I have very little confidence in what that underlying structure may be, although faceting, crusts and surface hoar development have been reported from various parts of the region. If I were traveling in the mountains, I'd maintain an investigative approach and dig down to test for weak layers before committing to a slope. If you've been in the mountains, please share your observations on our Mountain Information Network.