Steep Slopes Provide Cues to Debris-Flows

USGS debris-flow monitoring site in the Chalk Cliffs, Colo., study area. Debris flows in sparsely vegetated steeplands like those in central Colorado are often initiated by processes related to surface-water runoff after intense rainfall. However, the transformation of surface-water runoff into debris flow are not well understood. USGS scientists have begun monitoring debris-flow initiation in a small, steep catchment near Buena Vista, Colo., that produces between one to five debris flows every year. The results from this monitoring effort are being used to help constrain models of debris-flow initiation.