The deadliest natural disaster occurred when a hurricane struck Galveston, Texas, on September 8, 1900, killing over 6,000 people. Winds gusted to more than 100 miles (160 kilometers) per hour and a 20-foot storm surge (wall of water) crashed onto shore, entirely submerging the island. The hurricane dumped ten inches (25 centimeters) of rain on the island, as well. Almost every structure in town was leveled.
The costliest national disaster to date was Hurricane Andrew, which hit Florida on August 31, 1992, and Louisiana on September 1, 1992. Early warning kept the death toll to 58, but property damage came to over $30 billion. Over 200,000 homes and business were damaged or destroyed and 160,000 people were left homeless.
Sources: De Blij, Harm J. Nature on the Rampage, pp. 122; National Climatic Data Center. Billion Dollar U.S. Weather Disasters, 1980-1996. [Online] Available http://www.ncdc.noaa.gov/, November 19, 1996; Newsweek, vol. 120 (September 7, 1992), p. 23; Williams, Jack. The Weather Book, pp. 4-5.