Forecast snow fall amounts are uncertain: If you see more than 20 cm of new snow, it's time to dial back your terrain choices and take a close look at how the new snow is bonding to the old snow surfaces.
Confidence
Moderate - Forecast snowfall amounts are uncertain on Monday
Weather Forecast
Snow fall totals are uncertain Sunday evening into Monday, with 5cm on the low end and 20 cm being the upper end of forecast amounts. SUNDAY NIGHT: Snow. 5-15cm likely. Overnight lows near -5 Celsius. Light southerly winds.MONDAY: Cloudy with lingering flurries (up to 5 cm additional snow). Moderate westerly winds. Alpine temperature +1 C. Freezing level rising to 1600 m.TUESDAY: Cloudy with sunny breaks. Light westerly winds. Alpine temperature +2 C. Freezing level 1700 m.WEDNESDAY: Cloudy with sunny breaks. Light to moderate westerly winds. Alpine temperature +2 C. Freezing level 1800 m.
Avalanche Summary
On Friday and Saturday, several small wet loose avalanches to size 1.5 were reported on sunny aspects at all elevations. A size 1.5 natural cornice failure was also reported on a high north east facing ridge line, which did not trigger any slabs below.
Snowpack Summary
The last precipitation fell late last week, delivering snow to higher elevations and rain down low. Since then, the sun came out on Friday and Saturday, creating a melt-freeze crust on sunny aspects, but still leaving dry snow to be found on north aspects above 1300m.Thursday's snow fell on a previous melt-freeze crust produced by warm air temperatures, sun, and rain. The crust exists everywhere except for possibly shady aspects at high elevations. Deeper in the snowpack, the mid-December and late-November weak layers are composed of crusts and sugary facets, which are down 150-300 cm. These layers have been dormant but may be awoken by a large trigger, such as a cornice fall, or by humans traveling in thin-to-thick 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.