Flash Flood in Summit County, Ohio

Measured rainfall of 4 to 4.5 fell over Cuyahoga Falls on the evening of May 12th between 930 and 1130 pm. Doppler Radar Dual Pol estimated rainfall rates were in excess of 4 per hour around 945 pm. There was significant urban flooding as storm drains were overwhelmed by the excessively high rates. The return frequency for a rainfall event of this magnitude and duration is estimated around a 500 year event. Two adults needed to be rescued from a flooded basement on Dwight Street. Despite dozens of water rescues in the city proper, there were no fatalities or significant injuries. Most intersections in the city were impassable. Some roads near the Cuyahoga Valley sustained significant damage from overflowing creeks.

The City Hall sustained major damage as an estimated 30,000 gallons of water entirely from urban runoff filled their basement damaging $500,000 worth of computers. Approximately 1,000 homes sustained water damage, primarily to basements. Six homes were condemned due to extreme water damage. The flood was similar to the flash flood in 2003.

On the evening of May 12th a warm front tracking north over Lake Erie, reversed itself and moved back inland over northern Ohio. An organized convective complex with embedded supercells developed over north-central Ohio. Two confirmed tornadoes, one in Medina and the other in Lorain Counties, developed within this supercells. The slow movement of the storms combined with intense rainfall rates produced destructive flash floods across dozens of communities.