The region picked up 10 to 35 cm from the recent storm which could translate into surprisingly deep slabs, especially in wind exposed features near ridge crest. Tuesday is not the day for bold travel plans, keep it mellow as the snowpack adjusts to the new snow
10 to 35 cm of storm snow fell Sunday night into Monday. It seems to be most problematic in wind exposed features at and above treeline, a trend that is expected to continue into Tuesday.
The forecast is marked by a nice diurnal temperature swing with the freezing level rising progressively higher each day and then returning to valley bottom at night which is all well and good. Things change Friday night when the freezing level is expected to go to 2500 m (ish). Get the cold snow while you can.
MONDAY NIGHT: Freezing level at valley bottom, light variable wind, trace of snow possible.
TUESDAY: Scattered cloud cover, freezing level starting at valley bottom rising to about 1500 m, light southwest wind at lower elevations, moderate to strong northwest wind at ridge top, no precipitation expected.
WEDNESDAY: Broken cloud cover, freezing level starting at valley bottom rising to about 1500 m, light southwest wind at lower elevations, moderate to strong northwest wind at ridge top, no precipitation expected.
THURSDAY: Clear skies, freezing level starting at valley bottom rising to about 2000 m, light to moderate west wind at lower elevations, strong northwest wind at ridge top, no precipitation expected.
We're short on post storm observations, but control work produced storm slabs to size 1.5 Monday.
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 9th. This layer may become reactive again with a large trigger (like a cornice failure) or a sharp change in weather.
The Sunday/Monday storm produced 10 to 35 cm of storm snow which now rests on a variety of old surfaces including a firm crust on solar aspects, soft faceted snow and surface hoar in sheltered areas, and old wind slabs near ridge crest. The new snow has been formed into variable wind slabs in exposed terrain features, especially those near ridge crest.
A thick rain crust sits 30-60 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.
