Magnitudes, Patterns, and Causes of 20^th Century Floods in the United States

Abstract

During the 20^th century, floods were the number-one natural disaster in the United States in terms of the number of lives lost and property damage. The deadliest flood of the 20^th century claimed more than 6,000 lives, people who drowned in the storm surge from a hurricane that inundated Galveston, Texas, in 1900. The costliest flood on record was the $20 billion flood on the Missouri and upper Mississippi Rivers and their tributaries during the summer of 1993.

For more than 110 years the U.S. Geological Survey (USGS) has measured flood magnitudes for the Nation's benefit while supplying additional streamflow data with its extensive stream-gaging network. Near real-time flood information is now available for most streamflow-gaging stations nationwide via the World Wide Web.

One measure of the degree of flooding throughout the United Stat es can be determined by examining the percentage of streamflow-gaging stations that experienced a significant flood (top 10% of the annual floods for each station's period of record) for each year. Time series of the percentage of stations experiencing signigicant floods nationwide and by region showed no significant trends during the period 1920 to 1998. However, there were systematic fluctuations in the time series thay may be a result of climatological factors. El Niáo indices, solar-irradiance variations, Northern Hemispheric temperatures, and stratospheric wind velocities were compared with the national and regional flood time series and with individual basin flow series to ascertain possible relationships. The most significant relation was between solar-irradiance variations and floods.

Additional information on Floods in Kansas can be found at: http://ks.water.usgs.gov/waterwatch/flood/

Perry, C.A., 2000, Magnitudes, patterns, and causes of 20^th century floods in the United States [abst.]: Geological Society of America, Abstracts with Programs, Reno, Nevada, November 9-18, 2000, p. A508.

To request a paper copy of this abstract, email: cperry@.usgs.gov