Triggering storm slab avalanches is a concern in steep terrain as the new snow needs more time to strengthen.
Persistent weak layers have gained strength over the past week, but it may still be possible to trigger large avalanches on buried surface hoar or crust layers found 50 to 100 cm deep, especially on convex slopes at upper elevations.
Recent snow has settled into a 20 to 30 cm thick slab and remains likely to trigger on wind loaded slopes and possible to trigger at lower elevations where it may sit above sun crusts or feathery surface hoar.
TUESDAY NIGHT: Cloudy with isolated flurries bringing up to 5 cm of snow, moderate wind from the southwest, treeline temperatures drop to -5 C.
WEDNESDAY: Mostly cloudy skies with some convective flurries bringing localized accumulations of 5-10 cm, light wind from the south with moderate gusts during flurries, treeline temperatures reach -2 C with freezing level reaching 1500 m.
THURSDAY: Mostly cloudy with isolated flurries bringing up to 5 cm of snow, light wind from the northeast, treeline temperatures around -5 C.
FRIDAY: Mostly sunny, light wind from the northeast, treeline temperatures around -8 C.
Storm slabs were reactive on Monday with numerous small (size 1) human triggered avalanches at treeline elevations and a few reports of larger (size 2) natural avalanches in the alpine. These avalanches occurred in the top 20 to 30 cm of new snow. We suspect storm slabs were also touchy on Tuesday, but will gradually stabilize over the coming days.
The last report of a persistent slab avalanche was on Feb 20, which was a size 2.5 avalanche triggered by a cornice. While persistent slab activity has declined, we are uncertain about how persistent weak layers will react to warming and the weight of the recent snow.
Recent storm snow has likely settled into 20 to 30 cm of heavy powder at upper elevations and wet/crusty snow below 2000 m. Reactive slabs remain possible on wind loaded slopes and perhaps some isolated areas where this snow sits above sun crusts or feathery surface hoar. Two potential weak layers exist within the upper snowpack: the mid-February layer (down 40 to 60 cm) and the late-January layer (down 100 cm). They both consist of surface hoar and/or melt-freeze crusts. The reactivity of these layers has declined over the past week.
