MOUNT VERNON, Wash. (AP) -- The trucker was hauling drilling equipment when his load bumped against the steel framework over an Interstate 5 bridge. He looked in his rearview mirror and watched in horror as the span collapsed into the water behind him. Two vehicles fell into the icy Skagit River.
Amazingly, nobody was killed. The three people who fell into the water escaped with only minor injuries.
Officials are trying to find out whether the spectacular collapse of a bridge on one of the West's most important roadways was a fluke -- or a sign of a bigger problem with thousands of bridges across the U.S.
Authorities focused first on trying to find a temporary span for the Skagit, although it won't come in time for the tens of thousands of Memorial Day vacationers who would travel between Canada and Seattle.
"You cannot overstate the importance of this corridor to Washington state," Gov. Jay Inslee said. Traffic on I-5 and surrounding roads was backed up for miles, a situation the governor said would continue indefinitely.
Officials were looking for a temporary, pre-fabricated bridge to replace the 160-foot section that failed, Inslee said Friday. If one is found, it could be in place in weeks. If not, it could be months before a replacement can be built, the governor said.
The spectacular collapse unfolded about 7 p.m. Thursday on the north end of the four-lane bridge near Mount Vernon, about 60 miles north of Seattle and 40 miles south of the Canada border.
"He looked in the mirrors and it just dropped out of sight," Cynthia Scott, the wife of truck driver William Scott, said from the couple's home near Spruce Grove, Alberta. "I spoke to him seconds after it happened. He was just horrified."
The truck driver works for Mullen Trucking in Alberta, the Washington State Patrol said. The tractor-trailer was hauling a housing for drilling equipment southbound when the top right front corner of the load struck several of the bridge's trusses, the patrol said.
Scott, 41, remained at the scene and cooperated with investigators. He voluntarily gave a blood sample for an alcohol test and was not arrested.
Scott has been driving truck for 20 years and hauling specialized loads for more than 10.
"He gets safety awards, safety bonuses ... for doing all these checks, for hiring the right pilot cars and pole cars," his wife said.
Initially, it wasn't clear if the bridge just gave way on its own. But Washington State Patrol Chief John Batiste blamed it on the tall load.
The truck made it off the bridge, but two other vehicles went into the water about 25 feet below as the structure crumbled.
Dan Sligh and his wife were in their pickup heading to a camping trip when he said the bridge before them disappeared in a "big puff of dust."
"I hit the brakes and we went off," Sligh told reporters from a hospital.
Bryce Kenning, of Mount Vernon, said the bridge seemed to explode in front of him. The 20-year-old slammed the brakes and could see the edge of the pavement approaching, but there was nothing he could do.
"It was like time was frozen -- like a roller coaster where you're not attached to the tracks," Kenning said in a phone interview. "I'm sure it was just one of the loudest sounds ever to hear this thing explode and fall into the water like that, but I didn't hear a thing. I just witnessed it happening in front of me."
Ed Scherbinski, vice president of Mullen Trucking, said in an interview with The Associated Press that state officials had approved of the company's plan to drive the oversize load along I-5 to Vancouver, Wash., and the company hired a local escort to help navigate the route.
Mike Allende, a state Department of Transportation spokesman, confirmed the truck had a permit.
"We're still trying to figure out why it hit the bridge," Allende said. "It's ultimately up to the trucking company to figure out whether it can get through."
State officials approved the trucking company to carry a load as high as 15 feet, 9 inches, according to the permit released by the state. However, the southbound vertical clearance on the Skagit River bridge is as little as 14 feet, 5 inches, state records show. That lowest clearance is outside of the bridge's vehicle traveling lanes, Transportation Department communications director Lars Erickson said Friday. The bridge's curved overhead girders are higher in the center of the bridge but sweep lower toward a driver's right side.