Freezing levels could rise as high as 2900m on Sunday leading to a rise in the danger level, possibly up to HIGH. Avalanches are expected. Forecasters are still being cautious in steep and large terrain features due to several buried weak layers.
Confidence
Good - Timing or intensity of solar radiation is uncertain
Weather Forecast
Sunday will bring lots of sun and very warm temperatures with freezing levels expected to rise to 2900m. The ridge of high pressure will break down on Sunday night with a chance for very light flurries on Monday, but still warm conditions.
Avalanche Summary
Widespread loose dry avalanches were observed up to size 1.5 on steep lee aspects at all elevations. A few loose wet slides up to size 1.5 were also seen on solar aspects. ski cutting was producing small sluffs in steep north facing terrain.
Snowpack Summary
10cm of new snow fell at treeline overnight. Storm snow totals are now near 25 to 30cm, but are settling quickly due to the warm afternoon temperatures. The snow was turning moist on solar aspects by midday, so a sun crust is expected tomorrow morning that will break down through the day. In alpine and treeline areas, buried wind slabs are present, and the February surface hoar remains a concern buried up to 140cm.
Problems
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.
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.
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.