Enough snow should accumulate by Saturday for our newest weak layer to start showing off. Monitor new snow amounts and reactivity and manage the rising hazard with low-consequence terrain.
Buried persistent weak layers have produced large natural and human-triggered avalanches recently. Additional snow load may increase sensitivity to triggering.
New snow is expected to bond poorly to old surfaces including crusts and widespread surface hoar. Storm slabs are most likely to fail in wind loaded areas where sufficient snow has been deposited to overload the weak interface.
Persistent slabs were reactive on the February weak layer earlier this week, predominantly in the alpine. Naturals up to size 3, explosive controlled up to size 3.5 and skier remotes up to size 2.5 triggered from 100 m away. By Wednesday, reports of avalanche activity tapered dramatically.
Looking forward, new snow means an increase in likelihood of both surface avalanches as well as renewed possibility of large persistent slab avalanche activity.
By Saturday morning 15 - 25 cm of new snow should have accumulated on a widespread layer of large surface hoar crystals, which sits on a crust on solar aspects and at low elevations. This should produce reactive or even touchy surface instabilities.
A layer of facets, surface hoar and/or a crust from mid February are buried 50 to 100 cm deep. This layer produced large natural and human-triggered avalanches earlier this week.
The remainder of the snowpack is well consolidated with no concerns at this time.
Friday Night
Cloudy with easing flurries finishing with about 5 cm of new snow. 25 to 45 km/h southwest ridgetop wind, easing. Freezing level to valley bottom.
Saturday
Mostly cloudy with scattered flurries. 20 km/h southeast ridgetop wind. Treeline temperatures -6 °C. Freezing level 700 m.
Sunday
Cloudy with scattered flurries, negligible accumulation. 10 to 20 km/h south ridgetop wind. Treeline temperatures -7 °C. Freezing level 700 m.
Monday
Cloudy with increasing flurries bringing 5 - 10 cm of new snow, continuing overnight. 30 - 40 km/h south ridgetop wind, increasing. Treeline temperature -7 °C. Freezing level 700 m.
More details can be found in the Mountain Weather Forecast.
