The hot and sunny weather persists on Friday, which will likely continue the avalanche cycle on sunny slopes. The danger will be the highest when the day heats up, so make sure you are out of avalanche terrain early and with no overhead exposure.
Weather Forecast
THURSDAY NIGHT: Clear skies, light southwest wind, alpine temperature 4 C, freezing level 3000 m.FRIDAY: Clear skies, light southeast wind, alpine temperature 4 C, freezing level 3000 m.SATURDAY: Cloudy with light snow in the high alpine and rain below, accumulation 1 to 3 cm, light southwest wind, alpine temperature 0 C, freezing level 2200 m.SUNDAY: Cloudy with snowfall, accumulation 5 to 10 cm, light southeast wind, alpine temperature -3 C, freezing level 1700 m.
Avalanche Summary
Many wet loose avalanches were observed between Sunday and Wednesday. They were large (up to size 3), occurred mostly on southeast to southwest aspects, and at all elevations. A notable persistent deep slab avalanche was also triggered on Wednesday, likely from a cornice fall. It was 100 cm deep on a northeast aspect at 2900 m.This avalanche cycle is expected to continue on Friday, as temperatures remain exceptionally warm and the sun shines strong. The cycle may end on Saturday, as freezing levels drop and cloudy skies prevail.
Snowpack Summary
The warm air and sunny skies have produced wet snow to ridge top on southerly aspects and up to around 2100 m on northerly aspects. The upper 20 to 30 cm of snow may slide easily during the day, either as loose wet snow or as a cohesive slab, as it sits over weak faceted grains or a melt-freeze crust. The wet snow may freeze into a melt-freeze crust overnight.A weak layer of faceted grains and/or feathery surface hoar crystals buried in mid-January may be found around 50 to 90 cm deep. Although this layer has been dormant for a few weeks, the current warm conditions may awaken this layer. Steep cutblocks and large open glades at lower elevations are the most likely places to trigger this layer.The base of the snowpack is composed of weak faceted snow, which may be associated with a melt-freeze crust. The warm air and sunny skies has increased the likelihood of triggering very large avalanches on this layer.
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.
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.