Today marks the 25th anniversary of the 1996 Happy Isles rockfall. At 6:52 pm on July 10, 1996, two blocks with a combined volume of about 30,000 cubic meters and weighing about 90,000 tons broke loose from high on the southeast part of Glacier Point, hitting the valley floor near Happy Isles. In terms of volume, this equates to about 2000 SUVs dropping onto the valley floor at the same time. The impacts of the blocks generated an airblast with wind speeds up to 280 miles per hour, comparable to