2:22 p.m. The area came under a flash flood warning from the National Weather Service. The warning was publicized through several media sources and posted in all of the park's contact stations. Canyons were closed to canyoneering. 4:30 to 5:30 p.m. Zion Canyon received 0.63 inches of rain in less than one hour. Rangers noted Keyhole Canyon and several other canyons began to flash flood. The flow of the North Fork of the Virgin River rose abruptly from 55 Cubic Feet per Second (CFS) to 2,630 CFS in 15 minutes. The park receives levels this high approximately once every three years.