New slabs may form up high. There's uncertainty in how Tuesday's warming will impact the snowpack. Best to adopt a conservative mindset and dial back your terrain choices.
Wind slabs may be found at high elevations above the rain-snow line. Use caution in steep, lee terrain features. Use particular caution if you are finding more than 20 cm of fresh snow, as the resulting slabs could be deep and touchy.
Warm air will push into the region over the day on Tuesday and into Wednesday morning. The warming has the potential of triggering wet loose avalanches, which could step down to deeper layers where they exist.
MONDAY NIGHT: Cloudy with no precipitation, 40 km/h southwest wind, alpine temperature -4 C, freezing level 1500 m.
TUESDAY: Morning snowfall then mix of sun and clouds, accumulation 5 to 10 cm with up to 30 cm possible in the north, 60 to 80 km/h southwest wind, alpine temperature 1 C, freezing level rising to 2400 m.
WEDNESDAY: Cloudy with rain switching to snow, accumulation 10 to 20 cm snow above the rain-snow line, 40 to 60 km/h west wind, alpine temperature 0 C, freezing level 2000 m dropping to 1400 m.
THURSDAY: Clear skies with no precipitation, 10 km/h southwest wind, alpine temperature -6 C.
A few wind slabs were observed in the region on Sunday, being small to large (size 1 to 2) and on variable aspects. No other avalanches were observed.
Looking forward, avalanche activity may pick up on Tuesday into Wednesday with a rise in the freezing level. There's uncertainty in exactly what the warming will do to the snowpack, so adopting a conservative mindset will be important.
5 to 10 cm of snow is forecast for Tuesday, with locally higher amounts possible in the north. The snow will fall with strong southwest wind, forming wind slabs in lee terrain features in wind-exposed terrain. The storm is also coming with warm air, raising the freezing level to around 2400 m by the late afternoon. There's uncertainty in what this warming will do, but it has the potential of destabilizing the snowpack and triggering avalanches.
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.
