Avalanche Forecast

Good

A series of Pacific frontal waves and upper troughs will bring continued unsettled weather through the forecast period. Light -moderate precipitation amounts can be expected daily. With fast moving systems, timing seems to be hard to pinpoint. A strong upper SW flow will provide warmer the normal temperatures, rising freezing levels in the afternoon, then falling during the night. Things should start to cool off significantly by Friday. Wednesday: Snow amounts 5-10 cm. Ridgetop winds moderate from the South. Freezing levels 900-1000 m. Thursday/Friday: Light precipitation both days. Ridgetop winds mod-strong from the SW. Freezing levels 900 m, falling to valley bottom. on Friday.

On Monday, 1 natural cornice failure triggered a slab avalanche size 2 on the slope below. This was on a NE aspect around 1300 m. Other operations have reported no new avalanche activity through their tenures.

Moderate southerly winds have formed wind slabs in the alpine, and at treeline on lee and cross-loaded terrain. North aspects at higher elevations hold dryer, low density snow in the upper 20 cm. Spring-like conditions exist and crusts have formed on solar aspects at all elevations, becoming moist under sunny skies. Melt-freeze conditions exist below treeline on all aspects. Below this sits a well consolidated, settled mid pack. The mid February persistent weak layer, comprised of spotty surface hoar, facets and crusts, is buried 80-120 cm below the surface. No recent activity has been reported on this interface, although I feel that triggering may be possible in steep, isolated terrain in some parts of the region. If an avalanche occurs on this weak interface it will be very large and destructive. Below this the snowpack is well settled and strong. Cornices in the area are reported to be very large. Cornice failure could trigger an avalanche on the slope below.