The swath laser was tested at the large-scale experimental USGS debris flow flume facility as a potential tool for mass movement detection. The tests were conducted during gate release experiments, where a large volume of sediment was released from a hopper; and during natural release experiments, where a sediment prism was watered until wide-spread Coulomb failure occurred. During the gate release experiments, the swath laser measured arrival time and flow depth and data were compared with co-located laser rangefinder and the flume's analog laser (benchmark laser). During the natural release experiments, the swath laser measured geomorphic changes associated with the failure.