The snowpack is in transition to Spring conditions, but it is not there yet. Danger levels will rise on solar aspects with solar radiation and daytime heating. A poor freeze is expected Wednesday night. Ski quality remains poor in most areas.
Confidence
Fair - Timing or intensity of solar radiation is uncertain
Weather Forecast
A mix of sun and cloud for Wednesday with strong winds from the west. Temperatures will be mild with freezing levels rising to 2200m. Very light precipitation is possible on Thursday under a mix of sun and cloud and mild temperatures.
Avalanche Summary
A size 2.5 slab avalanche occurred in the past 24 to 48 hours on a steep south-west aspect at 2700m on Snow Peak. The avalanche was a wind slab, but it is suspected to have been triggered by solar radiation in the shallow snowpack start zone. Several loose wet avalanches up to size 2.0 have also occurred on steep south, south-west and west aspects in the past 2 days.
Snowpack Summary
Widespread wind effect in the alpine and open areas at treeline. These areas exhibit hard wind slab, soft wind slab, sastrugi, breakable wind crust and everything in between. Solar aspects were moist to 2600m, but sheltered polar aspects stayed dry all dry. The November facets/depth hoar combo persists and has been responsible for a couple of recent natural and human triggered slides.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.