Debris flow probabilities of ungaged tributaries to the Colorado River in Grand Canyon, AZ

This dataset represents 763 tributary canyons and/or watersheds adjacent to the Colorado River in Grand Canyon with associated debris flow probabilities from 2004. Also, these data include tributary canyon and/or watersheds to Glen Canyon and several smaller watersheds in Grand Canyon where debris flow data is currently unavailable. Historic probabilities of debris flow occurrence were estimated by modeling the known frequency distribution with drainage basin parameters observed to control the process by which debris flows initiate and travel to the river. Observations from 1984 through 2003 provide a 20-year record of all debris flows that reached the Colorado River in Grand Canyon, and repeat photography provides a 100 year record of debris flows from 147 tributaries. Owing to the limitations of the initial datasets and the focus on geomorphic change in the river corridor, debris flow probabilities pertain only to debris flows that reach the Colorado River.