25 to 30 cm of warm snow is expected Monday night. Human triggered avalanches are likely Tuesday, especially in steep wind-loaded terrain above treeline. Choose conservative lines and watch for clues of instability.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Continued precipitation is expected through Monday night before a brief lull in the action Tuesday and Wednesday. Thursday's system looks pretty juicy, stay tuned for details. MONDAY NIGHT: Overcast, freezing level around 1200 m, snowline around 1000 m, moderate southwest wind, 25 to 30 cm of snow.TUESDAY: Overcast, freezing level around 1000 m lowering through the day, moderate west wind, no snow expected.WEDNESDAY: Overcast, freezing level around 800 m, light scattered wind, up to 5 cm of snow possible. Up to 30 cm possible Wednesday night.THURSDAY: Overcast, freezing level may rise as high as 1200 m, strong west wind, 15 to 30 cm of snow possible.
Avalanche Summary
On Monday storm slabs were sensitive to skier triggering to size 1.0 on northwest through southeast facing features with crowns 10 to 15 cm in depth.
Snowpack Summary
As of Monday afternoon, 20 to 40 cm of rain soaked snow had fallen on the January 7th crust. Looking down into the snowpack there are a few prominent melt-freeze crusts that were buried mid-December and are now 50 to 100 cm below the surface. After heavy rain last Friday penetrated most of the snowpack, these crust layers have been reported to be bonding to the snow above and below. The rain last week has reduced the snowpack depth at 1000 m to about 140 cm and many early season hazards are still present.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.