At 8 a.m. on this date 45 years ago, the center of erstwhile Hurricane Agnes – and it never got beyond a Category 1 – was off the Delmarva coast on its way to executing one of the more-Byzantine journeys in the history of tropical cyclones.
By the time it had arched back toward New York and looped southwestward to all the way to near Pittsburgh, the remnants of Agnes and a powerful co-conspirator would become one of the deadliest and costliest tropical storms on record.
The storm was blamed for the deaths of more than 115 people and caused more than $12 billion in damages in today’s dollars.
The cosmic rains that swelled the Schuylkill and the Susquehanna River set off catastrophic flooding. So much rain fell in the Wilkes-Barre area that coffins floated out of graveyards.
Significant rains fell for three days, centered on June 22. More than 4 inches was measured in Wilkes-Barre and Allentown, with better than half of that on the 22nd. About 3.5 descended on Philadelphia.
Almost 18 inches was reported in Shamokin, Schuylkill County.
The Schuylkill at Reading crested at a record 31.3 feet, according to the National Weather Service; flood stage is 15.5.
The Susquehanna River reached 65.54 feet at Marietta, Lancaster County; flood stage is 49. The Schuylkill at Norristown rose to 14.65 feet, 3.65 above flood level.
The basin-wide rainfall averages for both rivers were in the 8-inch range, according to the government’s post-storm report.
Agnes couldn’t have done it alone, and it didn’t.
It had moved due north from Yucatan strengthening to a low-grade hurricane, with peak winds at 85 mph, in the Gulf of Mexico then weakening to a depression after making landfall near Panama City, Fla.
It later regained tropical-storm strength and migrated off the Outer Banks into the open Atlantic. It made landfall again at the western end of Long Island and merged with a mid-latitude storm over Pennsylvania.
Agnes was yet another example of the inadequacies of the 1-to-5 Saffir-Simpson scale, which grades hurricanes only by peak winds.
A Category 1 for winds, but if such a scale existed for rainfall, it might have been a 5.