New snow has landed on surface hoar and crusts.
Check the bond between new snow and the old surface before committing yourself to avalanche 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.
10 - 20 cm of new snow has fallen 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.
Saturday Night
Mostly cloudy with 1 to 4 cm of snow. 20 to 40 km/h south ridgetop wind. Treeline temperature -6 °C. Freezing level to valley bottom.
Sunday
Mostly cloudy with 0 to 1 cm of snow. 20 to 30 km/h south ridgetop wind. Treeline temperature -6 °C.Freezing level 700 m.
Monday
Cloudy with 0 to 4 cm of snow. 10 to 20 km/h south ridgetop wind. Treeline temperatures -7 °C. Freezing level 700 m.
Tuesday
Cloudy with flurries. 30 - 40 km/h south ridgetop wind. Treeline temperature -7 °C. Freezing level 700 m.
More details can be found in the Mountain Weather Forecast.
