Interstate 40 in Tennessee and North Carolina remains closed more than four months after the historic and catastrophic flooding from Hurricane Helene in 2024. The North Carolina Dept. of Transportation continues emergency repair efforts there and across the region.

According to the National Weather Service, the 12-20 in. of rain Helene brought to the Southern Appalachians on Sept. 27 came right on the heels of another rain event, which brought 8-20 in. to western North Carolina in the previous week—exacerbating the flooding and causing damaging events like landslides. The impacts were catastrophic.

A December report from the North Carolina Office of State Budget and Management estimates the costs to the state resulting from Helene at $59.6 billion, including $44.4 billion in direct damage, $9.4 billion in indirect or induced damage and $5.8 billion in potential investments for mitigation.

An estimated 73,000 homes were damaged, entire communities lost access to core services and communication, and roads and bridges were damaged at more than 6,900 sites.

In Chimney Rock, a temporary road has been constructed to provide access for work crews and residents ahead of permanent repairs to the highway that was washed out during Helene.
Photo by Derek Lacey for ENR

Among the most consequential road damage is the roughly four-mile stretch of I-40 where emergency shoring repairs are underway, including 10 sites that have been identified as the major areas in need of repairs, says Dru Miller, project development engineer for GeoStabilization International. In four of those, the eastbound lanes were swept away or heavily damaged and the westbound lanes were showing tension cracks.

“Essentially, what we’re doing is stopping the bleeding,” Miller says. “There was a potential that they were going to lose some of those westbound lanes, and if they lost those, they’re not getting any traffic through there.”

The most pressing objective was saving what roadway remained, he says. Crews installed soil nails into the embankment and into bedrock, followed by a 20-ft to 30-ft-tall band of shotcrete across the embankment at the most critical sites. Four sites were stabilized in late 2024. Since then, five subsequent priority sites have been identified, and that’s where work is going on now, Miller adds.

But initial plans to open the two westbound lanes to traffic by New Year’s crumbled on Dec. 18 when another section of the shoulder, Site 8, collapsed into the river. That sent the project back to square one in that area and delayed the planned reopening of the highway until this spring. As of Jan. 15, emergency shoring at four of the 10 locations, Sites 1, 6, 7 and 9, have been completed, with the team able to complete an average of about 775 sq ft per day.

“We were ahead of schedule for our portion of the work, so the team was excited to meet or exceed the original timeframe,” Miller says. “Mother Nature had other plans.”

The channel of the Broad River was moved in multiple places following the storm.
Photo by Derek Lacey for ENR

The Dec. 18 failure spot was on the team’s radar since the initial storm as one to monitor, but the failure occurred abruptly due mainly to the initial scour from the storm-swollen river in September. The subsequent freeze-thaw cycle and other rain events were factors as well. The main area of the Site 8 slide was roughly 150 ft in length, Miller says, although the repair area will extend beyond that for a total of about 450 ft. Repairs will be the same as in other stretches of the repair area: soil nail anchors and reinforced shotcrete.

“I’ve never seen anything like this,” says Miller, who has worked for the geohazard mitigation specialist for around nine years. “It just shows the magnitude of this river picking up these large stones and just hurling them into the embankment, carving into it.”

As the river eroded the embankment below the interstate, it peeled back the decades of work that have gone into constructing and repairing the interstate section, formerly known as Pigeon River Road. Essentially, the inboard side was blasted to make room for the roadway, which was then constructed with the material from the blasts, Miller says.

“It’s metamorphic rock,” he says. “So the material we’re drilling into is embankment fill material placed by humans at some point, and we’re getting through that into the native bedrock, which is quite variable.”

At a height of roughly 50 ft from the river, soil nailing along the bank is requiring remote-controlled equipment in some cases.
Photo by Derek Lacey for ENR

Staying Above Water

Before the storm, transportation officials received some weather briefings and knew the impacts could be near historic, says Kenny McCourt, NCDOT Division 14 resident engineer. They were expecting something akin to previous hurricanes that have hit the region, but Helene was a surprise.

“We were prepared for some isolated flooding ... so we were geared up,” he says, explaining that they expected maybe a two- or three-day turnaround until they would be able to hand the work off to contractors. “When we got the call about I-40, that’s when it really hit us.”

When he and Daniel Ross, assistant resident engineer, reached the site, the Pigeon River was roughly 30 ft above its normal level. It was deafening, with the sound of trees snapping and boulders colliding. When they reached the state line, they had to shout across to Tennessee Dept. of Transportation officials doing the same assessments from the west. Cellular service and internet service were down, so they made plans to meet again the next day at 10 a.m.

“It’s hard to fathom how much water was coming through here that first day,” McCourt says. “All we knew was we had to start thinking quick on our feet and try to come up with a game plan on how to save this.” On the way back to the office, they looked down on the town of Clyde from a highway bridge and only rooftops were visible above the water, Ross remembers.

“It looked like something out of a horror movie,” McCourt says, recalling inspecting I-40 the day of the storm. “This road is so well traveled, and to have nothing on it and the river roaring next to you.”

Eventually, NCDOT was able to connect to the internet via StarLink, and Verizon was able to set up a mobile unit at the local NCDOT yard. But initially, all work was being completed on paper maps, and teams were communicating via word of mouth, using surveying stakes to mark which sites had already been evaluated, McCourt says.

“Within a week and a half we covered all the miles,” Ross adds. “We knew what our damage looked like. We had it all out in paper, then everything came back online.”

They didn’t waste any time. Within 11 days after the storm, the project was awarded and contractor Wright Brothers mobilized quickly on the $8.5-million contract, which was expanded to include additional work and five more sites totaling more than $25 million. Within 15 days, drills were in place and soil nails were being installed. State DOT geotechnical engineers were on site to provide immediate recommendations for pinning the roadway to avoid losing this critical North Carolina-Tennessee connection—which under normal operation sees about 26,500 vehicles per day.

Overall, roughly four miles of shoulder loss occurred on I-40 headed toward the Tennessee line, affecting five previously constructed walls. The slope height in the area is 80 ft, according to NCDOT, with a vertical distance of approximately 50 ft from highway to river. The first four sites were stabilized Dec. 6. Two days later, paving and rumble strip milling began. On Dec. 9, curb installation on the westbound lanes began and was completed Dec. 23. The day after Christmas, Site 10 was stabilized.

Work has continued at pace; as of late January, four crews had installed nearly 75,000 sq ft of soil nails, a total of about 3,200 individual nails at an average depth of 25 ft. More than 2,500 cu yds of shotcrete have been applied, and 20,200 linear ft of 9-in. painted curb have been installed on the westbound lanes in preparation to open two-way traffic through the gorge.

A normal rate for one drill is approximately 1,000 sq ft of soil nails and shotcrete per week, McCourt says. Crews on I-40 installed roughly 50,000 sq ft in 90 days, with four drills working 12-hour shifts six days a week.

On Dec. 18, Site 8 suffered a failure that required the project team to extend the projected completion date beyond Jan. 1.
Photo courtesy GeoStabilization International

Starting From Scratch

To the southeast of Asheville, work is progressing on more emergency repairs in Chimney Rock, where the Helene-swollen Broad River washed away buildings and large sections of US 64/74, which serves as the town’s main street.

The roadway, lined by historic hotels, local breweries and restaurants as well as homes, was washed away entirely in large sections, leaving the state DOT to first reestablish access to the area. Crews set to work clearing trees and other debris to open the highway leading to Chimney Rock from Hendersonville, says Mike Patton, NCDOT Division 14 resident engineer. They first cleared enough to get an ATV through, then enough for vehicles and equipment, then finally enough for one vehicle to pass another. They were able to clear about 200 ft of road a day, he says.

“There was nothing left,” Patton says. “We got to a point down there where there wasn’t any point in going any farther because there was no road. There was nothing. It was river [and] woods.”

The day after the storm, Nathan Tanner, assistant division construction engineer for NCDOT hiked the 2.5-mile-plus stretch of damaged and destroyed highway, thinking about how long it might take to reconnect either side of that portion with emergency access.

“I was setting milestones for myself as we walked through there,” he says. “I was thinking if we could get halfway by Christmas, we’d be doing good. We had it all done by then.”

Crews have rerouted the river channel, which moved due to the storm to where the highway had been. Then, using reclaimed material and fill brought in from elsewhere, work started on a temporary road to give locals and workers access to the project area in preparation for permanent repairs.

In all, it took about two and a half months to restore connections and some level of temporary road between Chimney Rock and its neighboring town Bat Cave, Tanner says. Temporary roads were constructed in areas that were reclaimed by changing the river channels.

The Pigeon River scoured under Interstate 40, exposing bedrock and layers of fill from decades of construction and repairs.
Photo courtesy GeoStabilization International

“We really didn’t have any other options,” he says of potential strategies for restoring access. “We had private property and public access completely cut off. It was definitely an emergency response operation to do what we needed to get that back open.”

Work continues on the temporary road, which includes bridges constructed with old rail cars. This summer, portions of it will be paved so it can maintain traffic longer while permanent repairs get underway, he says. It’s been a heavy lift, with a lot of machinery, a lot of material and a lot of people, Patton says, some of whom worked 95 hours per week just after the storm.

“It’s one thing to repair infrastructure,” he says. “We lost everything ... there simply wasn’t a road where there’s been a two-lane road for hundreds of years. It was gone—and not just the road; everything.”

As of late January, much of the temporary gravel road has been constructed in the riparian area with room for permanent reconstruction of the highway later. Utility poles in the area are all temporary, installed by Duke Energy simply to restore electricity to residents remaining in the town. AT&T enlisted the help of a local kayaker to run a line down the river from the start of the project area to the town.

At Chimney Rock, and on I-40, NCDOT is turning to alternative delivery methods to speed work and stay flexible as conditions continue to change. That includes progressive design-build contracts. But the agency has also pursued construction manager/general contractor (CMGC) contracts. Even the typical bid-build contracts have been moving faster thanks to those at the project site as well as those in cubicles in Raleigh working long hours to get it done, Patton says.

“Both are methods we gravitated toward because of their speed,” Tanner says.

As with I-40, permanent repairs are yet to be designed, although future resilience will be a factor. Patton notes that in areas affected by Helene, more modern infrastructure fared relatively well.

Current standards are the baseline, Tanner says, although designs for permanent repairs may include grouted fills to stabilize slopes and prevent future scour as well as incorporating the latest hydraulic data to develop those plans with the future in mind.