Locally heavy snowfall is possible, which could bump the danger to considerable at treeline on Tuesday in specific areas. Wednesday and Thursday's forecast is highly uncertain. Check in daily for updates.
Confidence
Poor - Timing, track, or intensity of incoming weather is uncertain on Wednesday
Weather Forecast
Tuesday: 5-10cm snow. Strong to gale south-westerly winds. Freezing level at valley floor.Wednesday/Thursday: Weather models show very different outcomes. Anything's possible - from dry conditions to moderate (locally heavy) snowfall, with strong westerly winds and a slight rise in temperature. Confidence is poor. Check in tomorrow for an update.
Avalanche Summary
We haven't had any reports of new avalanche activity.
Snowpack Summary
Up to 30cm recent snow fell with little wind. This overlies older wind slabs, which appear to be well bonded. New wind slabs are likely to form quickly at the first sign of wind, as plenty of loose snow is available for transport.Besides new storm/wind-related concerns, the layer we're still watching in the region is a surface hoar layer buried in early December. It's down about 85cm in the Flathead and exhibits hard, sudden planar/full propagation results, meaning that's it's stubborn to trigger but could create a large avalanche if triggered.At the bottom of the snowpack a variable facet/crust/facet sandwich is located with depth hoar up to size 5mm below the crust, and facets size 2mm above. There has been little in the way of recent activity on basal layers.
Problems
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.