We use a high-resolution regional atmospheric model coupled to a hydrological model, and an off-line routing module to simulate a hydrograph during the 1996 July flash flood that occurred in the Saguenay region of eastern Qu¿bec. The hydrograph is at the outlet of the Ha! Ha! Lake in the Ha! Ha! River basin. The former has a drainage area of 250 km2 and is covered by 6 model grid squares; the precipitation at these grid squares compare well with observations at the nearest available rain gauge located 20 km south of the basin. The hydrological model is a modified version of a land surface scheme which consists of three soil layers, and the routing module is based on the geomorphological unit hydrograph. The simulated hydrograph is compared with another reconstructed hydrograph in the published literature.