Flooding From Hurricane Agnes

June 27, 2002


Provided by: Bucknell University
Summary authors & editors: Jim Foster

Thirty years ago this month, Hurricane Agnes caused some of the worst flooding ever in the northeastern US. With property damage totaling over $3 billion, it was the nation's costliest disaster for 20 years, until surpassed by Hurricane Andrew in 1992.

All-time record peak stages (water levels) and discharges (streamflows) were measured on many streams in New York and Pennsylvania. Along the main stem of the Susquehanna River from the New York-Pennsylvania border to its mouth on Chesapeake Bay, this was the greatest flood since at least 1784. Peak flows from Harrisburg, PA (shown above being flooded by the Susquehanna River) downstream to the Chesapeake Bay were in excess of 7.5 million gallons per second (1 million cubic feet per second).

Agnes became a category 1 hurricane over the southeastern Gulf of Mexico on June 18, 1972. After landfall along the Florida Panhandle coast, it weakened to a tropical depression but regained tropical storm strength over eastern North Carolina on June 21. The next day, Agnes again made landfall near New York City, with just under hurricane strength winds. Though its winds quickly subsided, it still produced copious quantities of rain. Agnes remained nearly stationary for several days and on June 23, its merged with a non-tropical low pressure system. This new system affected the northeastern US until June 25. Rainfall was widespread across the Middle Atlantic and New England states with totals ranging from 6 to 12 inches (15 to 30 cm). However, in some locales, rainfall totaled 14 to 19 inches (36 to 48 cm). Devastating flooding occurred from Virginia to New York, claiming 113 victims. Nine others died in Florida.

Related Links: