Weather Forecast
A high pressure ridge is once again set to bring dry conditions with warm alpine temperatures.Thursday: Dry. Alpine temperatures initially cool, around -5C, but rising late in the afternoon. Ridgetop winds light, up to 15 km/h from the NW. Friday and Saturday: The inversion is fully in place, with a strong above freezing layer from around 2300 to 3400m. Expect some Valley cloud, that may actually be quite high in places, and strong alpine sunshine. Ridgetop winds 10-20 km/h from the NW.
Avalanche Summary
On Wednesday, sluffing and very thin wind slabs were observed size 1 in steep terrain in the recent new snow. On Tuesday, explosive avalanche control produced avalanches up to size 2 that ran on the basal facets on N and NW aspects in the alpine. No natural activity has been reported for several days.
Snowpack Summary
The recent dry, warm weather has generally consolidated the upper snowpack. Old, stubborn hard wind slabs may exist under a skiff of new snow. Steep, sun exposed features are most likely seeing a daily melt-freeze cycle.A basal facet/crust combo (weak sugary snow above and below a crust) near the ground is still a concern in some areas. The depth of this layer makes triggering an avalanche on it unlikely (maybe a heavy load on a thin spot in steep terrain, rapid temperature change, or cornice fall), but the consequences would be large and very destructive.
Problems
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.