Bridge section collapses on I-5 north of Seattle SEATTLE - A large section of a bridge on Interstate 5 north of Seattle collapsed Thursday evening, sending vehicles and people plunging into the swirling, icy waters of the Skagit River. The bridge failed without warning between the towns of Burlington and Mount Vernon on the major route linking Seattle with the Canadian border, the Washington State Patrol said. Several witnesses told local TV that a vehicle carrying a large, oversize load crossed the bridge and struck it just before it collapsed. Other witnesses saw girders falling. PHOTOS: Bridge collapse in Washington Witnesses said several vehicles were in the water, and at least two people could be seen atop their vehicles, surrounded by the twisted steel beams of the bridge, as they waited to be rescued. The Skagit County sheriff reported that three people had been pulled out of the river. State patrol officials said they could not say how many vehicles fell from the bridge until they did a complete inspection. A sheriff's rescue boat was on scene and rescue crews were looking for people in the water as helicopters hovered overhead. Jacob Matson, who was in a nearby gym, said a loud crashing sound could be heard as the structure collapsed. "It had just fallen into the river," he told the Los Angeles Times. It just kind of sounded like a boom, a thud. Emerson Shotwell and Christian Sweet were headed north on the freeway when traffic came to a sudden halt about 7 p.m. "Everyone had to slam on their brakes," said Shotwell, 24, of Puyallup, Wash. From 60 to zero. Sweet, 22, of Bonney Lake, Wash., said they were probably just seconds from driving onto the bridge. Had they been running just a little earlier, he said, "We'd be in the water right now." About an hour later, the two sat in their car about 600 feet away. Traffic was still stalled, and the bridge was blocked off by authorities, Shotwell said. He and Sweet could see ambulances and police cars ahead, and they could hear sirens and see firetrucks minutes after the collapse. Later, they joined the crowd assembled on the bank, which erupted into applause as rescuers pulled a young boy from a pickup in the water. Shotwell said he saw that the boy was being treated, but he could not see if or how severely the child was injured. Bart Treece, a spokesman for the Washington State Department of Transportation, said the bridge was built in the 1950s but was regularly inspected, most recently in November. "We're still trying to piece together what happened," he told The Times. Our concern right now is getting people north and south, as I-5 is a pretty heavily traveled route. Electrical utility operators controlling a dam on the Skagit River above the bridge were reportedly working to reduce flows on the river to aid rescue and recovery efforts. Murphy reported from Seattle, Rojas from Los Angeles. Stephen Ceasar in Los Angeles contributed to this report. Boy Scouts of America lifts ban on gay youths Mexican drug cartel leader pleads guilty in 2011 ambush Oklahoma tornado toll at 24 dead, 377 hurt as recovery speeds up