The warm to cold temperature trend has helped to stabilize the storm snow, but we still have a lingering deep persistent slab problem in play which makes it impossible to have 100% confidence, especially in bigger alpine terrain features.
Watch for thin wind slabs immediately lee of ridge crest, especially in more extreme terrain. Also be aware of the potential for cornice failure, large cornices overhang many ridge lines at this time
Weak snow at the bottom of the snowpack hasn't gone away unfortunately. Cornice failures become more likely during these kinds of conditions and a failing cornice could be the perfect trigger for the deep persistent slab. Human triggering would be most likley around steep rocky terrain features, or anywhere the snowpack is thin and weak.
Warmer funky weather is with us for the forecast period.
SUNDAY NIGHT: Freezing level near valley bottom, moderate southwest wind, no significant precipitation expected.
MONDAY: A few clouds in the morning building to overcast after lunch, freezing level beginning near valley bottom rising to 1800 m during the day and then staying there until Wednesday evening, light southwest wind at lower elevations, strong west/northwest wind at mountain top, no precipitation expected.
TUESDAY: Mostly cloudy with potential for a bit of sun mid-day, freezing level holding around 2000 m, moderate to strong west/southwest wind, no significant precipitation expected during the day, 4 to 6 mm of precipitation falling as rain at lower elevations, snow in the alpine on Tuesday night.
WEDNESDAY: Mostly cloudy with potential for some clearing in the late afternoon, freezing level holding around 1900 m through the day, moderate west wind, 4 to 6 mm of precipitation falling as rain at lower elevations, snow in the alpine.
One of our field team members got out for a flight Friday, and she found a slab avalanche on a steep east/southeast facing alpine feature. Aside from that and a bit of loose wet activity on solar aspects, there has been little reported recent avalanche activity.
The most recent deep persistent slab activity we know about is described in this MIN report from February 11 and this MIN report on February 9.
The South Rockies picked up at about 7 cm of snow Saturday night accompanied by moderate to strong wind out of the southwest which has formed thin wind slabs in high elevation terrain, especially that immediately lee of ridge crest.
Under this new snow is a crust that may extend as high as 2300 m on solar aspects. It is present on all aspects to 1700 m.
A thick rain crust sits 40-80 cm below the surface and can be found up to 2100 m. Avalanche activity was last observed at the faceting interface between this crust and overlying snow on February 17.
The mid-pack is well settled and strong, but the base of the snowpack contains basal facets that are most prominent in shallow rocky start zones.
