With the longterm forecast calling for a tenacious ridge of high pressure to keep things cool and dry into the new year, it would be wise to get out and take advantage of the great start we've been having to the season.
Weather Forecast
Flurries will tapper off through Tuesday morning as a ridge of high pressure embeds itself over our area, total expected snow accumulations are 5-7cm. This ridge is forecast to persist through Thursday, giving seasonably cool temperatures (day time highs of up to -5 and overnight lows as low as -19) with light to moderate winds from the SW.
Snowpack Summary
Light snow is currently burying windslabs formed by this weekend's Mod-Strong SW winds. Below, old layers of settling storm and wind slab are interspersed with two thin layers of facets and possibly surface hoar which continue to slowly stabilize. This overlies the Dec 9th crust (down 50-90cm), still a concern as a developing weak interface.
Avalanche Summary
Several natural size 1-2 slab avalanches were observed yesterday, likely triggered by loading and slab development from the weekends wind event.
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 Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
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.