New snow and wind will mean that storm slabs are likely to be encountered, and may be reactive to human triggering, especially in wind loaded areas.
Confidence
Moderate - Intensity of incoming weather systems is uncertain
Weather Forecast
Freezing levels and alpine temperatures are difficult to forecast in the coming days with mild temperatures and temperature inversions dominating the weather pattern this week.WEDNESDAY NIGHT - Flurries, 10-15 cm / southwest winds, 40-60 km/h / alpine low temperature near -2THURSDAY - Mainly cloudy with isolated flurries, 2-5 cm / southwest winds, 20-40 km/h / alpine high temperature near -2 / Freezing level 1500 m FRIDAY - Cloudy with sunny periods / southwest winds, 10-20 km/h / alpine high temperature near 0 / freezing level 1400 mSATURDAY - A mix of sun and cloud / southwest winds, 10-20 km/h / alpine high temperature near +1 / freezing level 2000 m / alpine temperature inversion
Avalanche Summary
A size 1 human triggered wind slab avalanche on an east aspect at 1950 m was reported on Tuesday.A few reports of natural and explosives triggered avalanches to size 1.5 were reported in the region on Monday.
Snowpack Summary
15-30 cm of new snow combined with strong winds will be promoting storm slab formation at alpine and treeline elevations. The new snow sits on previous storm snow and wind slabs above 1500 m, and a melt freeze crust below 1500 m.In sheltered areas around treeline, 70-120cm of recent snow may sit on a weak layer of surface hoar (feathery crystals). In the east of the region near Corbin, a persistent weak layer that formed in early December may still be found 90 to 150 cm deep. This layer mostly consists of faceted (sugary) snow with some isolated areas also containing surface hoar. While professionals are still tracking this layer, it has not been reactive for some time now.There is a mix of crusts and facets that formed in late October/early November near the bottom of the snowpack. This layer may only be an issue on steep slopes where the snowpack is shallow.
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.