An up-slope storm centered on Waterton will substantially increase both ski quality and avalanche danger. The Danger Levels will depend heavily on how much snow we actually receive. Adjust your decision-making accordingly.
Weather Forecast
A strong upslope flow develops midday Monday, with snow to valley floor. Expect poor visibility and snowfall, heavy at times, ending midday Tuesday. Amounts differ wildly between forecasts: anywhere from 20 to 100cm in 24 hours, with initially strong NE winds at treeline and alpine elevations. Rising temperatures keep hazard elevated on Wednesday.
Snowpack Summary
Expect new snowfall through Monday & Tuesday to add a substantial amount of storm snow to the upper snowpack. This will bury small Wind Slabs that are difficult to trigger, lee to previous SW winds. These overlie a supportive Melt-Freeze crust which extends into the alpine on all aspects, and caps a strong and consolidated snowpack below.
Avalanche Summary
A widespread cycle of small, Loose Dry avalanches occurred on Friday. On Saturday, forecasters observed shooting cracks from their ski tips, propagating several meters. These cracked 40cm deep through recent wind slabs, isolated to ridgetop lee slopes.
Confidence
Forecast snowfall amounts are uncertain
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 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.