Avalanche danger can rise very quickly with warming and solar radiation. Be aware of changing conditions and overhead hazards. Terrain choices and timing can be critical.
Confidence
Fair - Timing or intensity of solar radiation is uncertain
Weather Forecast
An upper level ridge will keep the region fairly dry and sunny. Solar radiation will be strong, and freezing levels could rise as high as 2500 m by Sunday.Friday: A mix of sun and cloud with isolated flurries. Ridgetop winds moderate from the West. Freezing levels rising to 1800 m.Saturday: Sunny skies. Alpine temperatures rising to 5.0 degrees. Ridgetop winds moderate from the North. Freezing levels rising to 1700 m.Sunday: Sunny. Alpine temperatures high of plus 5-10 degrees. Freezing levels rising to 2400 m then dropping overnight. Ridgetop winds light from the SW
Avalanche Summary
Cornices have started to fail with warmer temperatures and sunny skies up to size 2.5, without pulling deeper slabs on the slopes below. Numerous loose wet avalanches occurred up to size 2 on steeper solar aspects, and one isolated size 3 slab was observed from a distance in the Northern part of the region. Natural avalanche activity will likely spike with periods of solar radiation and warming.
Snowpack Summary
Up to 20 cm of new snow sits above a solid melt freeze crust. The new snow seems to be bonding with help from the warmer temperatures; however, isolated wind slabs likely exist. Surface snow has become moist, especially on southerly aspects forming melt-freeze conditions and surface hoar growth (4 mm) has been noted on shady slopes at higher elevations. Large sagging cornices threaten slopes from above and below.Snowpack tests have been producing hard resistant planar shears on the late March layer and the upper snowpack has strengthened.A couple persistent weak layers exist deeper in the snowpack. The March layer is down 60 - 100cm and the February layer is now deeply buried down 150 – 250 cm. These layers are mostly inactive at this time, but could re-awaken with extended warming, solar influence and large triggers like cornice fall.
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.