A robust method to identify the occurrence of a runoff-generated debris flow

Debris flows generated by rainfall runoff can occur in rocky alpine landscapes and burned steeplands. Runoff-generated debris-flow events are commonly composed of a series dense granular surge fronts separated water-rich flows. Owing to this intra-event variability flow composition mechanics, post-event interpretations preserved sedimentary deposits, or lack thereof, result dizzying mix that range from clearwater debris flow. Accurate identification the presence absence during event is critical for building empirical models used predict likelihood occurrence, thresholds, properties. Here, we propose simple, quantitative method identify occurrence runoff-generated flow, based on dimensionless discharge Q * calculated as ratio peak p theoretical maximum rate w . Using preliminary compilation values floods flows, find 98% have < 1.6, whereas 91% greater than 1.6. Estimating typically straightforward part standard reconnaissance if suitable estimates available, appears be robust indicator traversed particular portion valley network.