CLYDE, NORTH CAROLINA — Crews have begun around-the-clock reconstruction of Interstate 40 through the Pigeon River Gorge in the Great Smoky Mountains, a multibillion-dollar effort expected to continue through fall 2028. Hurricane Helene's flooding in September 2024 destroyed portions of the highway, with some sections collapsing into the river.
The storm damaged nearly 12 miles of I-40 through the gorge in Tennessee and North Carolina. Engineers say the severity of damage varied because of differences in terrain along the gorge. In Tennessee, the valley is wider and shaped more like a football goalpost, allowing floodwaters to spread out. In North Carolina, the terrain narrows into a steep V-shape, intensifying the force of the river and increasing damage to the roadway.
North Carolina officials have described the I-40 reconstruction as the largest construction project in state history. Crews are using roller-compacted concrete and rock mixtures to rebuild two eastbound lanes suspended roughly 70 feet above the river. Workers are blasting rock from the Pisgah National Forest and transporting the material across temporary bridges built specifically for the project.
Project leaders say sourcing material on site reduces both cost and construction time. "Because of the remote nature of the project, hauling in rock from the local quarries in Tennessee and North Carolina would be extremely expensive and time-consuming. So we are saving roughly 30% in cost and time by getting material on site, making it here, and using it here," North Carolina Department of Transportation engineer Blake Soblesky said.
Soblesky said the rebuilt highway is engineered to handle a future storm of similar magnitude. "The intent of our design is to withstand a similar event such as Helene. We've put an extensive amount of time using hydraulics and hydrology analysis to determine what we think would be a similar event to Helene," he said.
By March 2025, crews had reopened the highway with limited traffic access, providing one lane in each direction while construction continues. The full North Carolina reconstruction is expected to run through fall 2028.
On the Tennessee side of the state line, repairs to I-40 are expected to cost nearly $245 million, with remaining work projected to wrap up by fall 2027. Tennessee transportation leaders recently marked the reopening of the final road and bridge repair project tied to Helene damage statewide, a bridge in Washington County that reopened in early May.