High-velocity transients observed near a sloping bottom are explained as solitary internal waves at the interface of the bottom mixed layer; the mixed layer is formed by overtuning of the boundary layer on the flooding tide. The wave occur during both ebb and flood and are excited by instability. A simple model of the bottom boundary layer, combined with simple criteria for instability and wave formation, yields parameter values in agreement with observations from the Hudson Submarine Canyon. ¿ American Geophysical Union 1989