Flooding from hurricanes is not the most common concern from these storms but in the case of Agnes it was the main source of all the damage.
Hurricane Agnes arrived in June, very early for a hurricane. It made landfall in Florida on June 19, 1972, where its impact was minor, before moving northeastward. The worst damage occurred in parts of northeastern Pennsylvania and upstate New York in the form of heavy rainfall. In Pennsylvania, Agnes combined with a low pressure area to produce widespread rains of 6–12 inches with local amounts up to nineteen inches in western Schuylkill County. There was widespread severe flooding from Virginia northward to New York, with other flooding occurring over the western portions of the Carolinas. The death toll from this storm was 122 and damage costs amounted to $3 billion.
The large disturbance that became Hurricane Agnes was first detected over the Yucatan Peninsula of Mexico on June 14. It drifted eastward and became a tropical depression later that day and a tropical storm over the northwestern Caribbean on June 16. Agnes turned northward on June 17 and became a hurricane over the southeastern Gulf of Mexico by June 16 and its continued northward motion brought it to the Florida Panhandle coast where it made landfall on June 19 as a category 1 hurricane. As it moved northeastward, Agnes regained tropical storm strength over eastern North Carolina and moved into the Atlantic later that day and so on to its disastrous rainfall regime over Pennsylvania and New York. There was a final landfall near New York City on June 22.
There was severe flooding along the Genesee River, the Canisteo River, and the Chemung River in southwestern and south central New York. The latter two flowed into the Susquehanna River that was already swollen due to winter snow runoff, and flooding continued all the way down this river. It set a flood record at, and threatened to overtop, the Conowingo Dam near the mouth of the Susquehanna in Maryland. The worst damage occurred in Elmira, New York, and Wilkes-Barre, Pennsylvania, but many other communities along the rivers suffered great losses. The Delaware River and Potomac River basins also had some flooding. So much fresh water was flushed into Chesapeake Bay that its seafood industry was badly damaged for several years. The James River in Virginia experienced five hundred-year flooding levels. Downtown Richmond was inundated.
The impact of Agnes on Pennsylvania was highlighted in the events at Wilkes–Barre on June 22. This industrial city on the River Susquehanna suffered a flooding when the river rose thirty-three feet above its normal level in 1936. Dikes were subsequently built to cope with a possible future rise of thirty-seven feet. On June 22, with water nearing the tops of the dikes, volunteers rushed to install a levee of sandbags on the dikes. It was in vain. The river reached forty feet and overtopped everything. By nightfall Wilkes–Barre’s downtown was under several feet of water, mud, and debris. Those who were able left for higher ground. The rest climbed to upper stories or roofs to await rescue. Electrical short circuits started fires in commercial warehouses, creating clouds of smoke that hung over the inundated city. Rats, flushed out of their holes, scuttled to the same rooftops that were serving as refuges for people.
People began to name hurricanes in the middle of the twentieth century and meteorologists decided to choose this as a more attractive method than using latitude and longitude for identification. First, women’s names were used then, in response to criticisms, names of men and women were employed alternately. An agreed list is established for each season. However, if a storm happens to be particularly destructive, its name is often taken off all lists permanently. The name is listed as retired. Agnes became a retired name after 1972.