A cooling trend is expected over the day, but the snowpack may remain unstable until it hardens. Assess for instability before pushing into big terrain.
New wind slabs may form above the rain-snow line with additional snow and strong southwest wind. Use particular caution if you are finding more than 20 cm of fresh snow, as the resulting slabs could be deep and touchy.
Wet loose avalanches may occur at all elevations until the freezing level drops over the day on Wednesday. Activity is most likely where rain is soaking a previously dry snowpack. Wet loose avalanches have the potential of stepping down to deeper layers, where they exist.
TUESDAY NIGHT: Cloudy with rain switching to snow, trace accumulation in the south of region and 10 to 20 cm above the rain-snow line in the north of the region, 60 to 80 km/h southwest wind, alpine temperature 0 C, freezing level 2300 m.
WEDNESDAY: Cloudy with snowfall, trace accumulation in the north of the region and 5 to 10 cm in the south of the region, 40 km/h west wind, alpine temperature -5 C, freezing level dropping to 1300 m.
THURSDAY: Clear skies with no precipitation, 10 km/h west wind, alpine temperature -7 C.
FRIDAY: Mostly cloudy with no precipitation, 10 km/h south wind, alpine temperature -6 C.
Minor avalanche activity was noted on Monday. A small wind slab was observed out of very steep terrain on a northwest aspect and small loose activity occurred below 1300 m.
Although not yet reported, we expect to receive reports of loose wet activity from the freezing level rise. Similar activity is anticipated Tuesday night into Wednesday morning and perhaps continue at lower elevations until the freezing level drops. Assess for wind slab formation at higher elevations.
Freezing levels reached the lower alpine, warming up the snowpack. With a freezing level drop over Wednesday, rain will switch to snow and the snowpack will begin to stabilize. Above the freezing level, wind slabs may be found due to new snow and strong southwest wind.
A weak layer may be found around 40 to 80 cm deep in the western half of the region. The layer consists of surface hoar crystals in treeline terrain in areas sheltered from the wind and otherwise a hard melt-freeze crust associated with weak faceted grains on sun-exposed slopes. Check out this blog for more information. This layer hasn't shown reactivity since last week but may still linger in portions of the region.
The remainder of the snowpack is well-bonded.
