May 12, 2014 Flash Flooding & Tornadoes

Overview

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 County, developed as a result. The slow movement of the storms combined with intense rainfall rates produced destructive flash floods across dozens of communities. Thousands of homes and businesses in northern Ohio were flooded. County-level emergencies were declared in Lorain, Medina and Summit counties. The rainfall intensity was around a 500 year event for many of the hardest hit communities.

Lorain County

Heavy rainfall, measured at 6.5 inches in 3.5 hours was measured by the Sheffield Village service department on the evening of May 12th. Runoff combined with routed water upstream from North Ridgeville and Avon caused the French Creek to rise 10 to 15 feet above flood stage in Sheffield Village. A half dozen buildings were flooded form the French Creek along with eight homes. The City of North Ridgeville sustained significant and widespread damage from flash flooding. An estimated 300 homes and 1,000 businesses sustained damage from the flood waters. The Mill Creek flooded condos on Mill Creek Boulevard resulting in 15 people rescued from the second floor or their homes.

Cuyahoga County

A dozen water rescues were conducted however no significant injuries were reported. In all nearly 1,000 homes were inundated in the towns of Olmsted Falls, North Olmsted, and Westlake. The City Hall in Olmsted Falls sustained significant flood damage to their basement. At the Great Northern Mall in North Olmsted 15 cars were submerged and a department store sustained significant damage. Dozens of roads and intersections were closed due to flooding with several feet of water.  Flowing water removed pavement from some streets in Strongsville and North Royalton.

Summit County

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. The return frequency for a rainfall event of this magnitude and duration is estimated around a 500 year event. Despite dozens of water rescues in the city proper, there were no fatalities or significant injuries. Most intersections in the city were impassable. 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.

In Akron 70 homes sustained basement flooding along with the Summit County Public Health Center. In Munroe Falls there was approximately $250,000-$300,000 in damages to city property. Numerous homes had sewer backup of 6 to 7 feet in basements. On Lindsey Road a house lost its foundation. Again, numerous water rescues were conducted in both Munroe Falls and Akron between 1030 pm and midnight.

The Stow/Silver Lakes region rain gages measured 4 to 4.5 inches of rainfall in an hour and a half between 930 pm and 1100 pm. The magnitude and intensity of the rainfall have a return frequency of a 500 year event. Infrastructure was overwhelmed by the runoff throughout the community. The hardest hit area was near State Route 91 and State Route 59 intersection where several businesses were damaged including a car dealership with 70 cars. The Holy Family Church and School sustained $3,000,000 in damages. Two homes suffered structural failures, one estimated as 4,000 square feet in size. There was even a debris slide at the Silver Lakes Condominium Complex on SR 59 which covered the parking lot with several feet of mud. In all, at least 100 homes were damaged. A number of water rescues were conducted by no serious injuries reported. The flood was comparable to the 2003/2004 floods, but was expected to result in the worst monetary damages than either of those significant events.

Medina County

Doppler Radar estimated between 2 and 4.5 inches of rain fell over Medina County on the evening of May 12th between 9 and 11 pm. The rainfall intensity caused rapid runoff and widespread flash flooding in the western and central parts of the county.  Dozens of roads and intersections were flooded from overflowing creeks. Flowing water removed pavement from main and side streets in Medina and Brunswick Hills. State Route 162, between the Interstate 71 overpass and River Styx Road in Montville Township, sustained major damage when a large culvert under the roadway was damaged. A fire truck sustained major damage when driving over a water covered and washout road in Medina along the River Styx. In Brunswick Hills 4.5” of rain was measured during the storms. Almost three feet of water flooded the Police Station. Small portions of State Route 303 and 252 damaged. The East Branch of the Rocky River, along with other tributaries to the Rocky River, was primarily responsible for the majority of the damage. The Plum Creek came out of its banks inundating an off-ramp from I-71 onto Ohio SR 3. Two water rescues were conducted at this site. Overall a dozen water rescues were conducted in western and central Medina County that evening, and an estimated 100-200 homes sustained water damage.