Front Range
SnowpackMarkus Beck · Dec 11, 2012 · Front Range
Weather
Cold temps, mostly clear skies with increasing clouds in the afternoon, light winds below TL, stronger above TL and especially at ridgetops. Not much windloading observed. No precip.
Snowpack
BELOW TL the snowpack consists of facets with 3-5mm DH at base. In most areas, a 10-20cm layer of soft 4F/F Storm Slab sits on top of these facets. Hs is variable 30-60cm avg. Snowpack structure is very weak but, at least for now, seems to be able to support the light new snow fairly well. As the new snow settles, I expect fracturing to become easier and propagation a bit more extensive. Additional snow load of 20-30cm will also start to upset this delicate balance. Currently, the most suspect areas BTL are steep open glades approaching 40dgr where the soft Storm Slab is at least 30cm thick. AT TL the snowpack is more variable both in depth and structure. Depth varies between a few cm to 90cm with ~50cm being most common. Structure is weak to very weak. Pre-storm snow has entirely faceted and is now covered by 20-50cm of soft 1F/4F Storm and Wind Slab; these slabs already have stiffened a little and are easily fractured producing shooting cracks running up to 50ft (observed). This is widespread and most pronounced on slopes 30dgr and steeper. In those areas that were snow free before the storm, stability appears stronger. ABOVE TL the snow pack varies most dramatically due to the recent strong winds. In some wind loaded terrain features, the snow depth might very well be several feet deep on top of the old pre-storm faceted snow. Since we did not travel that high up, we don't have any detailed snow obs here. Various snow tests (ski track tests, ski cuts, hand profiles, test slopes, dug up shooting cracks all point to a very sensitive snowpack. It is easy to fracture the snow and propagation is pronounced. Avalanches are limited in size due to the mostly shallow snow depth and patchiness of the faceted basal snow. Fractures were all on the interface with the old faceted snow and the new Storm and Wind Slab