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 early this week, with naturals up to size 3. Activity tapered dramatically by Tuesday.
A skier triggered a small (10 cm thick) wind slab that formed over our latest surface hoar layer on Thursday. Along with a renewed possibility of large persistent slab avalanche activity, it's a glimpse of what we should expect as more new snow accumulates.
By Saturday morning, 20 - 40 cm of new snow should have accumulated over a widespread layer of large surface hoar crystals, which sits on a crust on solar aspects and low elevations. This should produce a reactive or even touchy storm slab problem.
A layer of facets, surface hoar and/or a crust from mid-February are buried 50–100 cm deep. This layer produced large natural and human-triggered avalanches earlier this week and may be coaxed into action again by forecast snowfall or surface avalanches.
The remainder of the snowpack is well consolidated with no concerns at this time.
Friday Night
Cloudy with easing flurries and up to 5 cm of new snow. 30 to 50 km/h southwest ridgetop wind, easing. Freezing level to 700 m.
Saturday
Mostly cloudy with flurries bringing 5 - 10 cm of new snow and new snow totals to 20 - 40 cm, greatest toward the coast, continuing overnight. 30 to 50 km/h southwest ridgetop wind, increasing. Treeline temperatures -1 °C. Freezing level 1000 m.
Sunday
A mix of sun and cloud with isolated flurries. 30 to 40 km/h southwest ridgetop wind. Treeline temperatures -2 °C. Freezing level 900 m.
Monday
Cloudy with increasing flurries bringing 5 - 15 cm of new snow, including overnight amounts. 40 - 80 km/h south ridgetop wind, increasing. Treeline temperature -2 °C. Freezing level 800 m.
More details can be found in the Mountain Weather Forecast.
