The governor of Georgia declared a state of emergency in Fulton County at 10pm last night after a powerful blaze caused the collapse of a section of elevated interstate highway a few miles north of downtown Atlanta.
Motorists are preparing for chaos now as the affected Interstate-85 is a major thoroughfare in Georgia and the southeastern US.
In declaring the emergency Governor Nathan Deal said the closure of the I-85 for the foreseeable future may have "far reaching social and economic consequences".
There were no immediate reports of injuries, and the incident is not thought to be an act of terrorism.
Governor Deal had said the fire appeared to have been fuelled by a large pile of PVC piping under the structure.
A spokesman for the Atlanta Fire Department said the blaze, which began around 7pm local time, was massive. "There was a 40-feet or higher wall of fire. Power lines were falling and arcing heavily and falling in the streets," Cortez Stafford told CNN.
The collapsed section bore the northbound lanes of the I-85, but the southbound section is also heavily damaged.
Georgia’s transport commissioner Russell McMurry today warned motorists to expect a lengthy disruption. The fire damage will require "extensive reconstruction activities", he said in a morning statement.
"We began design of the known damaged sections last night and continue designs as information is received," he said. "At this time, we do not have an anticipated duration for the repairs as we have not been able to fully access the site due to hotspots, but we do know that it is expected to be a time consuming event."
He confirmed that the area where the fire started is part of the state’s right of way that was used to store construction materials, including PVC piping, which he noted is "a stable, non-combustible material".
"We are as eager to learn the cause of this fire as anyone, which is why we will continue to work closely and in full cooperation with fire investigators to determine exactly how the fire was started," McMurry said.
Image: The Atlanta Fire Department said the flames under the I-85 reached 40 feet in height (Atlanta Fire Rescue/Twitter)