The cold temps have persevered the high quality powder skiing and riding. Enjoy the last turns of 2017 and a safe new year!
Weather Forecast
The all to familiar arctic high pressure system has not taken our hints this season and plans to crash the new years party tonight and will most likely hang around into mid next week. Expect sun with periods of cloud today, an alpine high of -12 and light westerly winds. Some forecast models show the return of snow at the end of the week.
Snowpack Summary
25cm of low density storm snow now buries the Dec 27 surface hoar/ facet layer. The Dec 15 surface hoar/sun crust layer, which is widespread at treeline, is buried down 60cms. Cold temperatures have hindered slab development in the upper snowpack. Expect to find pockets of wind slab in the alpine and open ares at tree line.
Avalanche Summary
We experienced a natural avalanche cycle yesterday with numerous loose dry and storm slab avalanches up to sz 3.0, mostly from steep, confined terrain. Be aware of naturals from above especially while traveling in confined valley bottoms as avalanches have the potential to reach into run-out zones.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.