ADA — It wasn't exactly the "Storm of the Century," but local officials now say last week's Monday morning flash flood did qualify as a "Hundred Year Event."

The June 19 storm officially dumped a little more than five inches of rain on Ada, with some areas of the county receiving as much as six inches of rain in just a few hours. Ada Emergency Management Director Gene Linton said the severity of the storm and the rate at which the water fell helped it meet the qualifications as a "Hundred Year Event."

"What that means is that this particular storm dumped rain at specified rate in a specified amount of time — so much so that statistics say it could happen only once every one hundred years," Linton said. "Or, you could look at it like this: There's only a 1 percent chance that we'll have a storm like that in the next one hundred years."

Rainfall began falling across western portions of Pontotoc County at around 8:30 a.m. Monday, with storms spreading into Ada by 9 a.m. In the next two hours, flood waters reached as high as four feet in some portions of Ada, stranding motorists and flooding some homes and business in a manner that many lifelong Pontotoc County residents said they had never seen.

Linton said several factors contributed to the deluge, including a line of thunderstorms that continued to blossom directly over Pontotoc County and moved at an unusually slow rate of speed.

"I went back and checked the radar information and saw that those storms were moving at between five and eight miles per hour," Linton said. "That's almost unheard of. But, when you consider that it was raining about two inches or more per hour, that's when you have real problems."

Linton said the worst part of the storm dumped 4.67 inches of rain on the city in less than two and one-half hours, qualifying it as a Hundred Year Event. The qualifying statistics are established by the Oklahoma Geological Survey and the Oklahoma Department of Transportation.

Linton said the fact that the storms kept "back-building" was also a contributing factor to the severe flash floods. Backbuilding is when a storm continues to build back away from the "target" (which was Pontotoc County, in this case) and that new growth then moves over the target in the same pattern as the original storm.

"Something else that was really strange was that the initial line of storms, the one that was moving across so slowly, was traveling east-southeast, but then we had another cell move directly south from Pottowatomie County that sort of joined up with that first storm and that's when the rain really went crazy," Linton said.

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