Stoddard footbridge over the Salmon River collapses

The Stoddard Bridge, located about 38 miles west of North Fork, collapsed recently. Courtesy Caryll McConnell, Idaho Department of Fish and Game

The Stoddard Bridge, located about 38 miles west of North Fork, collapsed recently. Courtesy Caryll McConnell, Idaho Department of Fish and Game

The Stoddard Bridge is an important access point for stock and hikers into the Frank Church River of No Return Wilderness area. Courtesy Caryll McConnell, Idaho Department of Fish and Game

SALMON — The only footbridge across the Salmon River providing access to the Frank Church-River of No Return Wilderness collapsed for unknown reasons and it is undetermined when the structure may be considered for reconstruction, Salmon-Challis National Forest officials said Friday.

The same day, forest safety officials and engineers were dispatched to the Stoddard Pack Bridge, about 38 miles west of North Fork and just downstream of the confluence of the Middle Fork Salmon and Salmon rivers, to assess damage and gather clues about the cause of its collapse.

A preliminary suspicion is that a rock or debris slide may have played a role in the event, which was reported to officials Thursday but which may have happened earlier this month, said Salmon-Challis spokeswoman Amy Baumer.

Baumer warned river users of possible debris and cables in the river channel and said the public should avoid the area as current conditions are hazardous.

The bridge adjacent to the Salmon River Road, considered crucial for wilderness access by outfitters, hunters, anglers and hikers, has a troubled history.

Allegations that the structure was unsafe arose about six years ago when a subcontractor working on a reconstruction of the bridge said it was unsafe. In a letter to the regional forester at the time, Scott Brown, head of Husky Timber Frames of Utah, said he and his workers were demolishing what remained of the trusses and decking in late August 2011 when the west end of the bridge slumped 14 inches.

“I cannot express to you the rush of fear that I and my four-man crew experienced,” Brown wrote in the letter.

The U.S. Forest Service had earmarked $222,000 for the bridge overhaul, which was overseen by Raass Brothers Inc. of Utah and which, in turn, hired Brown’s company. The contract called for replacing most of a structure originally built by the federal Civilian Conservation Corps in 1937. The replacement did not include cables under-girding the structure, which Brown alleged had been weakened by corrosion, making the bridge dangerous.

Brown’s alarms led the Forest Service and Raass Brothers to hire independent experts to inspect the cables in November 2011.

The firm hired by Raass Brothers found the condition of the segments of cable that were visible and not buried to be “very good” for materials exposed to the elements for many decades, according to a report released by the company. The firm cautioned that its report was limited to the sections of cable that allowed a hands-on inspection and not those that were inaccessible.

A separate inspector for the Forest Service found only minor abrasion and corrosion on the segments of cable he tested and concluded the damage would not compromise safety, according to the Forest Service.

Salmon-Challis National Forest Supervisor Chuck Mark said Friday that there were no ties between the concerns raised by the subcontractor and the collapse of the bridge.

In fact, the cables remained intact on the upper portion of the bridge after its collapse, which destroyed the decking, according to forest officials.

The open question about the bridge’s replacement or repair was bound to prove an inconvenience to those who use it, forest officials said.

“It is unfortunate that this has happened and it’s a great loss,” North Fork District Ranger Ken Gebhardt said in a statement.