Regions
South Coast Inland.
The highest snowfall amounts are for the south of the region. Observe for new slabs that may form with snow and strong winds. For the north of the region, be diligent around treeline, where a buried weak layer may still linger.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
SATURDAY NIGHT: Cloudy with snowfall, accumulation 10 to 15 cm, strong southwest winds, freezing level rising to 1000 m.SUNDAY: Cloudy with snowfall, accumulation 5 to 10 cm, moderate southwest winds, alpine temperature -5 C, freezing level 1000 m.MONDAY: Clearing over the day, light south winds, alpine temperature -6 C, freezing level 700 m.TUESDAY: A mix of sun and cloud, light northwest winds, alpine temperature -9 C, freezing level 500 m.
Avalanche Summary
A natural avalanche cycles occurred on Thursday in the north of the region, with large avalanches up to size 3. These avalanches ran within the storm snow as well as on the weak layer described in the snowpack summary.
Snowpack Summary
New wind slabs may form the storm today, which may sit on old wind slabs from Thursday’s storm. Below around 1800 m, expect to find a melt-freeze crust formed by rain from Thursday’s storm.In the north portion of the region and possibly the far south, a weak layer of facets and surface hoar lies below all this storm snow, around 100 to 150 cm deep. The weak layer appears most prominent around treeline, up to 2000 m. While the layer is likely gaining strength, field observations show that slab avalanches remain possible on this layer where it exists.Near the base of the snowpack, a crust exists with weak and sugary facets beneath it. This could potentially still be of concern in high north-facing aspects where the snowpack rests on very smooth ground cover.
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.
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.