News

July thunderstorm set early morning rainfall record in Alexandria

Water Levels at Cameron Run on July 9 (image via City of Alexandria)

A storm that postponed the city’s birthday celebrations last month set a rainfall record in Alexandria according to a floodwater mitigation newsletter prepared by the city.

The Flood Action Alexandria newsletter, prepared by Flood Action Alexandria communications specialist Amanda Dolasinski, noted that a storm on July 9 set the record for rainfall recorded before 7 a.m. The newsletter said the city saw nearly 4 inches of rainfall in the northeast section of Alexandria and pushed Four Mile Run to to the 10-foot stage at Shirlington Road Bridge.

“The Four Mile Run rain gauge in the northeast part of the City recorded 3.92 inches of rain at the 24-hour mark of the July 9 storm, with most rainfall recorded before 7 a.m.” the newsletter said. “The storm was classified as a 10%- to 12%-chance-per-year storm, meaning the rainfall produced exceeded the probability with a 10% chance of being equal in any given year.”

Despite the quantity of rainfall, the newsletter said the intensity was less dramatic and the city didn’t see the same levels of severe flooding as it has in the past.

“Fortunately, the intensities were less dramatic than in past large storm events,” Brian Rahal, a civil engineer for the Stormwater Management Division, said in the newsletter. “It appears the urban flash flooding was at a minimum.”