We toured into the Middle Fork today to check on conditions and collect more information about the distribution of our Deep Persistent Slab.
We observed two wet-loose avalanches on the north flanks of Mount Penrose. One D2, one D1.5, and both ran about 400 vertical feet and had a starting elevation of around 5000 feet. The Start zone slope angle is estimated at 38 degrees from CalTopo. The larger slide appeared to be 40 feet across, and its path's sidewalls were delineated. The bed surface was a melt-freeze crust.
We believe these ran late Thursday (1/20). This area looks to have received 6-8 inches of new snow from Thursday's storm. Late Thursday night, the snow turned to rain and, we assume, triggered these slides.
Forecast Hotline: 406.257.8402
Call or text an observation: 406.66AVYOB