The next bulletin will be published on Monday, December 09, 2013.
Weather Forecast
An arctic outbreak continues it's hold on the region today and tomorrow. Expect alpine temperatures of -19 deg C. Temperatures will slowly start to rise starting tomorrow, with more seasonal temperatures for Wednesday. Snow is in the forecast starting Tuesday/Wednesday.
Snowpack Summary
Surface facetting and new surface hoar growth is occurring. Windslabs are widespread above treeline. The November 28 surface hoar/crust interface is down 30-40 and the November 12 surface hoar layer is down 60-110cm. These layers are of most concern where the overlying snow has formed a cohesive slab.
Avalanche Summary
No new natural avalanches were observed yesterday. On Tuesday, a group reported easily ski cutting a few pockets of soft windslab in 8812 bowl. Earlier in the week, several large avalanches natural avalanches occurred. They all appeared to be 30-40cm deep, likely on the Nov 28 surface hoar/crust.
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.