Shown on a topographic map are floodmark elevations and approximate areas flooded by Hurricane Frederic tides of September 12-13, 1979, along the Mobile Causeway (U.S. Highway 90) from the Tensaw River to Spanish Fort, Alabama, and the eastern shore of Mobile Bay in the vicinity of Spanish Fort. Most buildings and business establishments along Mobile Causeway were completely destroyed, and the remaining buildings were severly damaged by flooding. 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)