Though Spring has not yet arrived to our snowpack, the intense April sun is having an effect - pay attention to rapidly changing conditions on sunny days. Good skiing is being found on sheltered northerly aspects.
Confidence
Moderate - Timing or intensity of solar radiation is uncertain
Weather Forecast
Tuesday looks to be mostly sunny with freezing levels climbing to at least 1800m. It will likely feel very warm in the sun. Winds will be moderate from the West. Conditions continue to warm up through Wednesday and Thursday.
Avalanche Summary
Solar triggered pin-wheeling and sluffing occurred on steep solar aspects, but generally not much mass was involved.
Snowpack Summary
Up to 10cm of new snow at Treeline in the past 24hrs, with much less at lower elevations. This snow was turning moist on solar aspects by late morning, and by tomorrow morning should be frozen into another in a series of previously formed crusts on these solar slopes. On polar aspects between 20 and 30cm of dry snow is currently on the surface, but buried crusts are found at lower elevations. Wind slabs are widespread in the Alpine on all aspects, but are more isolated at Treeline. Not much natural avalanche activity has occurred with these wind slabs, but many areas like ripe for human-triggering. As previously reported the mid-pack remains dense and strong, but the basal layers are very weak consisting of anywhere between 50 and 100cm of facets sitting on the ground. Forecasters still have low confidence for traveling in large Alpine terrain, unless there has been widespread previous avalanching.
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.
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.
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.