On this day in 1972, severe weather conditions over the Yucatan peninsula in Mexico begin to converge and form a tropical depression that would become Hurricane Agnes over the next two weeks. By the time the storm dissipated, damages were in the billions and 121 people were dead. Although incredibly strong winds hit the Florida coast, it was the immense amount of rain that the storm brought to the northeastern United States that proved to be most deadly.

Agnes was the first major storm of the 1972 hurricane season and it quickly raced across the Caribbean toward Cuba. On June 18, the speed of its winds reached 74 mph and it attained hurricane status. Apalachicola, Florida, took the brunt of Agnes as it hit the coastline; it suffered about $10 million in damages.

Georgia, South Carolina and North Carolina were the next states on Agnes’ path. Tornadoes and torrential rain buffeted the entire region and there was considerable flooding in the Blue Ridge Mountains. In all, an estimated 28 trillion gallons of water came out of the sky during the storm. Washington, D.C., saw so much rain that President Richard Nixon was unable to fly to the city in the aftermath of the Watergate break-in.

The worst flooding occurred in Pennsylvania and New York. The overflowing of the Susquehanna and Genesee Rivers killed 50 people in Pennsylvania, nearly half the entire casualty toll of the hurricane.