ASHEVILLE, N.C. (828newsNOW) — As Hurricane Helene barreled toward the Southeast coast, Chad Franklin received a warning from his NCDOT colleagues who specialize in stormwater and flooding management.
Engineers with the N.C. Department of Transportation’s Hydraulics Unit were poring over data, and they didn’t like what they saw. The agency’s flood-warning system predicted a mile of Interstate 40 near the French Broad River in Buncombe County would flood by 2 feet. That was Wednesday, Sept. 25, a day before Helene roared ashore in Florida.
“I was shocked when they told me that,” Franklin, an NCDOT regional intelligent transportation systems engineer for the state’s 17 most-western counties, said in a news release Wednesday. “It had never flooded before.”
As Topical Storm Helene approached Western North Carolina and the rainfall forecasts intensified, the flood tool predicted an even higher flood stage for I-40. Before daybreak on Friday, Sept. 27, Franklin dispatched the roadside assistance crews to I-40 near mile marker 47 (NC 191/Brevard Road). Crews were told to close the road immediately if it started to flood.
Torrential rains pushed the water over the banks of the French Broad River, and the murky water reached the pavement later that day. Franklin’s crews, other NCDOT staff and the N.C. State Highway Patrol turned on their flashing lights and used their vehicles to close I-40. The floodwaters eventually reached about 8 feet over I-40, NCDOT officials said.
“That flooding was more than we’d ever seen before in that area,” Franklin said. “Had we not closed it that soon, we might have had people driving onto a flooded highway, and the results could have been deadly.”
Instead, NCDOT and State Highway Patrol troopers were able to detour traffic onto I-240 around Asheville. I-40 reopened Saturday evening, Sept. 28, after the waters had receded.
During the storm, the flood tool was used to monitor and close a number of roads that quickly deteriorated as Tropical Storm Helene swept through WNC. Just as important, though, was NCDOT employees were getting important information from first-responders, law enforcement and emergency management officials to better respond to the storm.
“The flood warning tool did its job, and we’re grateful it did,” Franklin said.
Flood warning system proves valuable
The storm was the largest test yet for the department’s nationally recognized flood warning system since it became operational in 2022. The system provides critical, real-time information that helps NCDOT prepare for, respond to and recover from severe storms. With it, engineers are able to monitor more than 15,000 bridges and culverts and 2,000 miles of state-maintained roads, including Interstate 40.
“The system is made of three computer-based components that pull in all kinds of data from various sources,” NCDOT Public Information Officer Andrew Barksdale said. “We use this system to better inform our NCDOT employees on how to prepare for and respond to a storm.”
The flood warning system has proven instrumental in safeguarding North Carolina’s transportation infrastructure. During Tropical Storm Idalia, which led to significant flooding in eastern North Carolina, including downtown Whiteville, the system generated 109 alerts, enabling staff to proactively respond, the NCDOT news release said. During another event last summer in the mountains, an alert directed NCDOT’s bridge maintenance team in Polk County to inspect a bridge, which led to its immediate closure following the confirmation of storm damage.
During Helene, the department’s Hydraulics Unit identified process improvements for the flood warning system. The large volume of alerts created an overwhelming influx of text messages for NCDOT employees, and some river gauges went offline because of disrupted cell service, the news release said. To address these issues, the unit plans to implement a summary alert system during major storms to streamline communications. Additionally, the unit’s engineers are working on adding satellite communication capabilities to critical gauges to ensure reliable data transmission even during cell service outages.
“Our goal is to save lives,” State Hydraulics Engineer Matt Lauffer said in the news release. “So, we’re taking the lessons we learn from each storm and applying those to make this tool even better.”