Expect storm slab reactivity to increase throughout the day. Accumulating snow will further stress a weak layer buried on Christmas.
As new snow accumulates, storm slab likelihood and size will increase. The added load may trigger slabs on the Christmas crust, especially on wind-loaded slopes at treeline and above.
Explosive control work on Wednesday produced mostly small slab avalanches (size 1–1.5) in alpine terrain. Despite a strong, artificial trigger (explosives), these avalanches showed minimal propagation.
Numerous small skier-triggered avalanches occurred early this week, failing on the Dec. 25 crust. Most of these avalanches occurred on northerly terrain around treeline elevations.
New snow is gradually burying a variety of old surfaces, including surface hoar in wind-sheltered terrain and a sun crust on south-facing slopes at treeline and above.
Since Christmas, approximately 30 to 60 cm of snow has accumulated over a melt-freeze crust that is thin or absent in alpine terrain but thicker and more widespread at treeline and below.
The mid and lower snowpack is generally well-bonded and consolidated, with multiple crust layers present.
Friday Night
Cloudy. 2 to 8 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1100 m.
Saturday
Cloudy. 5 to 15 cm of snow. 40 km/h south ridgetop wind. Treeline temperature -2 °C. Freezing level 1600 m.
Sunday
Mostly cloudy. 10 to 30 cm of snow. 40 km/h south ridgetop wind. Treeline temperature -2 °C. Freezing level 1600 m.
Monday
Mostly cloudy. 5 to 15 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level 900 m.
More details can be found in the Mountain Weather Forecast.
