A cycle of small, Loose Wet Avalanches was the result of the temperature inversion, clear skies and calm winds today. The temperatures look to remain warm for the next two days at least.
Weather Forecast
Pacific air will continue to override cooler air in the valleys producing a temperature inversion through to Tuesday. Winds should remain light from the SW through Monday until late in the day Tuesday when they will increase and potentially bring some light flurries or rain.
Snowpack Summary
10-15cm of recent snow has blown into thin slabs TL and above. Old slabs, 10-40cm deeper, sit on a weak layer of facets or surface hoar TL and above. In sheltered areas the new snow sits a weak,faceted upper snowpack at all elevations. A strong mid snowpack crust is providing strength but is weakening. The lower snowpack continues to lose strength.
Avalanche Summary
A cycle of loose wet avalanches started on steep south slopes at midday and followed the sun onto West slopes into the mid afternoon. The inversion, calm winds, and strong sun all factored into these events which originated as high as 2900m and ran up to sz 2 in confined features. Only one slab was observed to be triggered by all of this activity.
Confidence
Timing or intensity of solar radiation is uncertain on Monday
Problems
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.
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.