Slow-Moving Storms Pose Biggest Threat To Stormwater System
Does your heart skip a beat during a downpour and make you wonder how long it will last? Last year’s flood may have heightened your senses to that.
With the potential for rain and thunderstorms through Friday, Chapel Hill stormwater management engineer Sue Burke says the only time the storm water system could be tested is if severe thunderstorms drop high amounts of rain in a short period of time.
“When we’ve had what we call high-intensity-short-duration storms, which means the rain is coming down at a really high rate over a very short period of time, the water then has trouble getting down into the storm drain system there’s just so much of it,” Burke says.
The Town saw 0.66 inches dropped on it Monday. It was spared the same storm Durham saw, which flooded some parts of the city after more than an inch of rain was reported at Raleigh-Durham International Airport. Some area’s may have seen more due to the trend National Weather Service Meteorologist Nick Petro says would present the biggest problems.
“The main concern will be poor-drainage flooding as any of these heavy showers are going to move slowly,” Petro says. “There not a whole lot of wind in the atmosphere. So, these things, when they move, they’re going to move very slowly, and they’ll have the potential to dump a lot of rain over any given area.”
Thursday and Thursday night come with the greatest chances of rain and thunderstorms at this point—although the chance of precipitation tops out at 50 percent during the day. The National Weather Service is predicting less than a tenth of an inch of additional rainfall each day, unless a severe storm hits.
Last year, more than two and a half inches of rain fell in the four days leading up to June 30 when 5.12 inches fell in less than 20 hours. Some Chapel Hillians remember that as the worst flood in some 30 years.