When dealing with persistent slab problems, keep in mind that even though the likelihood of triggering an avalanche decreases, the consequences remain high. Conservative terrain selection is recommended.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
SATURDAY NIGHT - Mainly cloudy with clear periods and isolated flurries / southwest winds, 15-30 km/h, gusting to 50 km/h / alpine low temperature near -11SUNDAY - Cloudy with sunny periods and isolated flurries / southwest winds, 20-40 km/h / alpine high temperature near -6MONDAY - Cloudy with sunny periods and isolated flurries / light southwest winds / alpine high temperature near -6, low temperature near -9TUESDAY - Cloudy with sunny periods / light southwest winds / alpine high temperature near -8, low temperature near -10
Avalanche Summary
Several explosives triggered avalanches size 1-2.5 were reported in the region on Saturday. No new natural avalanches were reported on Saturday.Several natural and explosives triggered avalanches to size 2 were reported on Friday.
Snowpack Summary
60-100 cm of recent snow has formed a slab that sits on a weak layer that formed in early December. This layer mostly consists of facets (sugary snow) with some isolated areas also containing small surface hoar (feathery crystals). Several other weak layers have been observed in the lower snowpack such as crusts and facets that formed in late October/early November.
Problems
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.