Minimize overhead hazard and make conservative terrain choices on Sunday.
A warm, wet storm is moving through the region starting tonight. 15-30 cm of snow with strong to extreme W winds will bump the danger rating to HIGH in the alpine & CONSIDERABLE at treeline. This new load may also make the buried persistent layers more reactive.
New snow, warm temperatures and strong west winds are expected to form touchy new wind slabs at treeline and in the alpine that will be easy to trigger. Cornice failures may also occur. Minimize overhead hazard and avoid wind loaded slopes until the new snow has time to bond with the old surfaces.
A facet or facet/crust interface 40 to 60 cm down, formed in late January, has been the failure plane for several large avalanches in the region this week. We have limited information on its spatial distribution, but this layer has been observed on all aspects and elevations.
Local ski areas were able to ski cut small wind slabs in the immediate lee areas of the alpine and treeline on Saturday.
No natural avalanches observed, but visibility was limited. Moist snow reported below 1900 m.
Scouring, wind effect and some small wind slabs exist in the alpine. The Jan 24 facet/crust layer is down 40-60 cm and producing variable moderate-hard sudden planar results with stability tests. The distribution of this layer is difficult to pin down, but it has been observed at all elevation bands. A thin temperature crust exists on the surface at lower elevations. The lower snowpack is generally strong.
Sunday: Forecasts snow amounts vary with 10-35 cm of snow by the end of the day, with the larger amounts expected along the divide. Strong winds from the West continue through most of the day. Freezing levels stay near 2000 m Saturday night, and begin lowering through the day on Sunday.
Monday: Freezing levels drop to valley bottom, winds become light, and snow flurries with a mix of sun and cloud are expected.
