A large section of the Hart Mine Road Bridge in southwestern Arizona collapsed after sustaining structural damage believed to have been caused by a recent wildfire.
The 557-foot-long bridge, located at the Cibola National Wildlife Refuge on the Arizona-California border, spanned the Colorado River before it collapsed on July 27.
No injuries were reported.
The Bureau of Reclamation, Bureau of Land Management, U.S. Fish and Wildlife Service, U.S. Army Corps of Engineers, and federal wildland fire crews are coordinating the emergency response and safety efforts, according to the Bureau of Reclamation.
Crews are installing buoy barriers and warning signs while taking other precautions to prevent vehicle, pedestrian, and boat access.
River safety teams are identifying and marking hazardous debris areas in the water to protect boaters and other recreational users.
“We are asking all pedestrians, motorists, and boaters to avoid the area at this time,” Resource Management Office Chief Chris Wallis said in a statement.
“With debris in the water and ongoing assessments underway, staying clear of the site is essential for everyone’s safety.”
Wallis said the bridge is owned by the Bureau of Reclamation and provides a Colorado River crossing near the Cibola National Wildlife Refuge.
It is used primarily for farm access and by Cibola personnel traveling to essential services, he said.
Officials said the collapse appears to be linked to the Island Fire, which burned through the refuge about 25 miles southwest of Ehrenberg.
The blaze began on July 25, and the area remains closed while firefighters continue suppression efforts.
As of July 28, the fire was 65 percent contained after burning about 3,145 acres, according to the interagency incident information system InciWeb.
The cause remains under investigation.
Wildfires burned more than 282,000 acres across Arizona in 2024.
The state recorded 2,191 wildfire incidents, nearly 400 more than the previous year, according to Frontline Wildfire Defense.
Arizona’s largest wildfire remains the Wallow Fire, which ignited on May 29, 2011, in the White Mountains. It burned 538,049 acres before firefighters fully contained it on July 8 of that year.
