Mader applied his expertise in fluid dynamics to research in the numerical modeling of tsunamis (1974) and other water waves. Using the full Navier-Stokes AMR (adaptive mesh refinement) Eulerian compressible hydrodynamic computer code called SAGE (SAIC Adaptive Grid Eulerian), software developed by SAIC and Los Alamos, he modeled landslide tsunami hazards, such as the 1958 Lituya Bay megatsunami (2002) and the 1883 eruption of Krakatoa (2006). His models are used to evaluate tsunami flooding and to determine which areas need to be evacuated.