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Yosemite Winter Rockfall Update, 4.1.23
For the winter storm period of 2022-2023 (October 1 to March 30), there were 69 documented rockfalls, rockslides, and debris flows, with a cumulative volume of about 19,000 cubic meters. These events resulted in two fatalities on the El Portal Road, two evacuation advisories for parts of Old El Portal, a 24-hour closure of the Horsetail Fall viewing area, and 18 instances of road closure. Although rockfall consequences were unusually high this winter, frequency/magnitude numbers are on par with previous wet winters – the same period in 2016-2017 had a roughly similar number of events (60) with an even larger cumulative volume (about 25,000 cubic meters)