A History of Danger and Cost

The main stem of the Susquehanna has flooded 14 times since 1810 – about every 15 years, on average. Even the Native Americans who once lived in the area told of frequent floods.

The Susquehanna Basin also is vulnerable to frequent, localized flash floods every year. These flash floods, usually affecting smaller tributaries, can occur with little advance warning.

Tropical storm Agnes in 1972 caused the worst recorded flooding in the basin. Seventy-two people died and damaged topped $2.8 billion – about $14.3 billion in today’s dollars. Flood levels exceeded the record levels of the 1936 flood by as much as six feet in some places. It was the nation's most costly natural disaster until Hurricane Andrew hit in 1992 and Hurricane Katrina in 2004.

Of the 1,400 communities in the river basin, 1,160 have residents who live in flood-prone areas. For these residents, flood warning and flood management and protection are of utmost concern.

Major Floods Since 1810

1810 1955 Hurricanes Connie & Diane
1865 1964
1889 1972 Tropical Storm Agnes
1894 1975 Tropical Storm Eloise
1935 1996 January Basinwide Flash Flood
1936 St. Patrick's Day 2004 Tropical Storm Ivan (September)
1946 2006