Modelers have found support for what meteorologists have long theorized—that hurricanes need warm ocean water to sustain their fury. Robert Tuleya and Yoshio Kurihara of the Geophysical Fluid Dynamics Laboratory designed a numerical model of a tropical cyclone running aground, an event that usually dissipates the storm. In seeking the specific mechanism that worked to diminish the storm the scientists devised three scenarios. In the first the ‘land’ was rougher and drier than the ocean. In the second the land area was rough but as wet as the ocean; in the third, evaporation was eliminated, but the land surface was as smooth as the ocean.