Vail & Summit County
AvalancheJason Konigsberg, Kreston Rohrig · Dec 5, 2017 · Vail & Summit County
Snowpack
The snowpack hasn't changed a lot since prior to the storm. The structure remains weak on north to east slopes and in most areas the slab is discontinuous, variable and generally thin. We experienced shooting cracks and small collapses near treeline on small terrain features but none of these obvious signs of instability were noted on bigger slopes.--- The recent wind drifted snow onto the leeward side of terrain features. This newly formed wind slab was stubborn to unreactive. The distribution was isolated and there wasn't enough of a continuous new slab over slopes with a weak snowpack structure to change the sensitivity of our Persistent Slab avalanche problem. The data we collected suggests that the Persistent Slab avalanche (PSa) problem was isolated and stubborn to trigger in the area we traveled.---On another note we dug a pit on a southeast-facing slope and found very weak snow below a 2-inch thick melt-freeze crust. There is no slab and the crust is too hard to be able to collapse the weak layer but this will be something to watch for future development. If the crust continues to facet we may have to watch southeast slopes for a PSa problem during the next loading event...whenever that may be.
Avalanche
One recent Wind Slab avalanche on a steep north-east facing slope. Surprisingly the avalanche ran at an interface or within new snow and not in old snow.