A catastrophic flash flood surged through Bright Angel Creek at the Grand Canyon on 29 August 2026, marking the national park's most destructive flooding event since 1966. Triggered by a dangerous convergence of the Arizona monsoon, a marine heatwave, and a heat dome drawing moisture from Tropical Storm Iselle, the rains intensified to 5 inches per hour over the burn scar of the Dragon Bravo Fire, causing water levels to rise over 5 feet in just 10 minutes. The dark, ash-laden floodwaters tragically claimed the lives of hikers John Giusti and Brent Rosenkranz, while their companion Timothy Allen Smith remains missing, even as about 82 people were rescued by helicopter and transported to safety. The raging torrents destroyed vital infrastructure including trails, footbridges, and the Transcanyon Waterline, while also triggering rockfalls and mudslides across the canyon. This widespread destruction forced Stage 4 water restrictions across the South Rim, leaving a permanent mark on the park's landscape and operations.