Aug. 29., the day that Hurricane Katrina barreled ashore on the Gulf Coast, also was the first day of class for Geology 428/528, "Preventing Geologic Disasters," at the University at Buffalo. Even though he had already prepared a semester's worth of historical examples, Michael F. Sheridan, Ph.D., UB professor of geology, decided that day to ditch much of it and to focus, instead, on Katrina as the harshest of case studies.