MAHONING VALLEY July was one of the wettest

The area passed its 50-year storm level once in July.
By DAVID SKOLNICK
VINDICATOR STAFF WRITER
YOUNGSTOWN -- It's a month we won't soon forget.
When it rained, it poured.
The Mahoning Valley experienced a month of heavy rains, 10.39 inches to be exact. That's good enough for the second most rainfall in a month in recorded weather history; 10.66 inches in June 1986 is the local record.
Almost half of that fell July 21, when 4.65 inches of rainfall was recorded at the Youngstown-Warren Regional Airport in Vienna, where the official count is made. That was the most rain to fall in a 24-hour period in the Valley's recorded weather history. Other communities reported rainfall of about 7 inches during the early part of last week.
The July rain caused major flooding in some areas, and left hundreds of basements damaged from water.
100-year storm level
The July 21 rain slightly exceeded the area's 50-year storm level, said Alan Ringo, a hydrologist with the National Weather Service in Cleveland, but didn't come near the area's 100-year storm level.
A 100-year storm is a certain amount of rainfall in a period of time that has a 1 percent chance of being equaled or exceeded; or a storm of such magnitude that it happens only once in 100 years. A 50-year storm is the same thing except the rainfall amount is supposed to happen only once every 50 years.
"It doesn't mean you can't have two 100-year storms in two consecutive days, just that it isn't likely," said Tim Burkert, a design construction engineer with the Mahoning County Engineer's Office. "It's like the lottery. You could get the same numbers in two straight days. Just because it happened once, doesn't mean it can't happen the next day."
The Valley's 100-year storm level is 5.25 inches for a 24-hour period, Ringo said. That is something that has never happened in the area's recorded weather history, which goes back more than 60 years.
The 50-year storm level for the Valley is 4.6 inches in a 24-hour period, which we slightly exceeded July 21, Ringo said.
Storm sewer capacity
While the storm level numbers may not mean a heck of a lot to the average person, they are important, Ringo said.
"It means a lot because many sewer systems are built to hold 25-year rainfall levels or less," he said. "When you have a 50-year rainfall, you've then got a problem. You've had a lot of rainfall so that compounds the problem."
County storm sewers are built to hold a 10-year storm level, which is 3.6 inches in a 24-hour period, while state highways are made to hold 25-year storm levels on less-traveled roads, and 50-year storm levels on major roads.
But the storm sewers weren't the only reason for flooding, Burkert said.
"We had a lot of streams and rivers overflowing that caused flooding," he said.
The Mahoning River at three different locations, in Youngstown, Leavittsburg and Braceville, hit record high levels last week.
National Weather Service meteorologists expect drier weather for August, September and October. But at least the first few days of this month are going to be wet.
Rain is predicted through Wednesday for the Valley, said Kirk Lombardy, a NWS meteorologist.
"This is an unusual summer," he said. "We're typically dry. But, obviously, that hasn't been the case this summer."
skolnick@vindy.com