Heavy rains caused flash flooding in parts of Lancaster County on Wednesday, closing parts of Route 30 East and spurring several water rescues and numerous wet basements.

Millersville University officially recorded 1.36 inches at its weather station, although much larger amounts were reported at some locations, including 5 inches at the city's wastewater treatment plant on New Danville Pike.

The cloudbursts made us wonder: What are the wettest days in Lancaster County history? Here's the answer, based on 102 years of data from the Millersville University Weather Information Center, which has records dating to 1914.

The chart below shows the 46 dates on which 3 or more inches of rain fell in one day.

Far and away, the biggest one-day rainfall total was generated by Tropical Storm Agnes, which sat over eastern Pennsylvania and parts of New York State for three days. Flooding took 72 lives and caused billions of dollars in damage.

On June 22, 1972, Agnes dropped 8.46 inches of rain on Lancaster County, leading to 10 deaths here and causing major flooding and damage in many parts of the county.

The second biggest total was 6.6 inches that fell on Sept. 18, 1927. That deluge resulted in the drowning of a child and forced the rescues of motorists from trees and residents from the roofs of their homes in Paradise, according to newspaper reports at the time.

The third biggest total was just five years ago, when officially 6.0 inches fell on Sept. 30, 2010, though localized totals ranged from 3.5 to 7 inches around the county. The torrential downpours forced schools to close early, prompted a state of emergency in Lancaster County and resulted in dozens of water rescues.

Worse flooding had occurred a year earlier, when the remnants of two storms — Hurricane Irene and Tropical Storm Lee — swept over the county a week apart. Irene dumped more than 3 inches of rain here in late August, and Lee followed up with nearly 9 inches over four days.

But the biggest one-day total during that stretch was 3.11 inches on Sept. 7, 2011, ranking it well down the list of wettest individual days here.

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