The snowpack in the South Rockies remains generally weak. The snow that fell over the past week sits on a persistent weak layer that will need more time to adjust to the new load. 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 -7MONDAY - Cloudy with sunny periods and isolated flurries / light west winds / alpine high temperature near -7, low temperature near -10TUESDAY - Cloudy with sunny periods / light southwest winds / alpine high temperature near -9, low temperature near -11
Avalanche Summary
No new avalanches were reported in the region on Saturday.One natural size 2 avalanche that was triggered by a cornice was reported in the region on Friday. One size 1.5 explosives triggered avalanche was reported on Thursday.
Snowpack Summary
60-90 cm of recent snow has formed a slab that sits on a weak layer of facets (sugary snow) that formed during the dry weather in early December. Avalanche activity on this layer has slowed down to some degree, but in certain terrain features, it may still be easy for humans to trigger avalanches on this layer. Steep features where the underlying ground cover is smooth, places where the snowpack transitions from deep to shallow, and large convex features are some of the most likely places to trigger this layer.The lower snowpack has a weak structure composed primarily of facets. It is likely that an avalanche triggered on the persistent slab would step down to the lower facets, resulting in a full depth avalanche.
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.