Shown on a topographic map are floodmark elevations and approximate areas flooded by Hurricane Frederic tides of September 12-13, 1979, along the southern shore of Perdido Bay, Ono Island in Old River, and Perdido Key exposed to the Gulf of Mexico. The most severe damage occurred along Perdido Key in Alabama and Florida where many homes were demolished and the highway was washed out in several places. Storm-tide frequency and records of annual maximum tides at Mobile, Alabama, since 1772, are presented. Offshore winds reached about 160 miles per hour. A wind-velocity of about 145 miles per hour was recorded near Dauphin Island, Alabama. (USGS)