Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Regions
South Rockies.
Substantial snowfall could accumulate by Monday morning. Treat the hazard as higher if you find more than 30 cm of new snow. Storm slab avalanches are likely -- conservative decision-making is recommended.
Confidence
Moderate - Intensity of incoming weather systems is uncertain
Weather Forecast
MONDAY: Cloudy with snowfall, accumulation 10 to 20 cm and possible localized higher amounts from convective flurries, light northeasterly winds, alpine temperature -15 C, freezing level below valley bottom.TUESDAY: Partly cloudy with light snowfall, accumulation 1 to 3 cm, light westerly winds, alpine temperature -9 C, freezing level 800 m.WEDNESDAY: Mostly cloudy, light southwesterly winds, alpine temperature -7 C, freezing level 1300 m.
Avalanche Summary
On Saturday, a large slab avalanche was observed around treeline in a forest burn. The feature is convoluted and of convective-nature. It is suspected that it was triggered by a snowmobiler. Check out the MIN report here for more information. Other wind slabs were noted in the region on all aspects.
Snowpack Summary
Around 10 to 20 cm of new snowfall is expected in the region. The new snow will fall on wind slabs at higher elevations and a melt-freeze crust on sunny aspects and all aspects at low elevations.Numerous crusts are found around 60 to 80 cm deep up to 2200 m. At a similar depth, a layer of surface hoar is found on shaded aspects at treeline in parts of the region.The midpack is well-settled and strong. This overlies sugary facets in thin snowpack areas.
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.