If the rain-soaked snow freezes as expected on the weekend, avalanche hazard will follow a decreasing trend until more snow falls late Sunday. Please treat this forecast as an initial assessment, as we have little information at this time.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
We're looking at relatively benign weather until Sunday afternoon, when a brief but intense cold front will bring 10-15 mm of rain and then 10-20 cm of snow by Sunday night. Sunday: 10-15mm of rain early afternoon changing to snow (10-20 cm possible overnight). Freezing levels 2200m decreasing to surface by the evening. Winds moderate from the south west. Monday: Scattered flurries. Freezing level around 1200 m. Moderate westerly winds.Tuesday: Isolated flurries. Freezing levels rising to 1700 m. Moderate southwesterly winds.
Avalanche Summary
Several loose wet avalanches to Size 3 (some digging to ground) were reported at the end of the rain event. Whether avalanches are still running is a different question and unfortunately the weather and lack of observers is making that hard to determine. I'd expect a decrease in avalanche activity with cooling temperatures on the weekend.
Snowpack Summary
The tropical punch during the week dropped upwards of 80mm rain (that's over 3 inches!) and resulted in a widespread wet upper snowpack. The freezing level rose to close to 3000 m on Wednesday and Thursday meaning very few places, if any, will have escaped the melt. Cooling temperatures after the rain resulted in widespread crusts which may break down with daytime warming.During the week, the snowpack also diminished by 20-40 cm. Below treeline snowpacks are at or below threshold and travel in this elevation band is rugged. Expect treeline snow depths of around 60 cm. A crust that formed around Halloween has been reported from neighboring regions and may still exist in the Lizard-Flathead region too, roughly 40 cm below the surface.
Problems
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.