Seattle, Washington - An Interstate 5 bridge collapsed into the Skagit River at around 7 p.m. Thursday evening, dumping at least two vehicles in the waters north of Mount Vernon.
A law-enforcement source said investigators believe a truck with an over-sized load heading south struck the bridge, which started bouncing, then fell.
The source said that 150 yards of the interstate dropped, sending a car, a truck and a travel trailer 120 feet down to the water.
"It's a hell of a ride," the source said.
All three people in those vehicles were rescued. They suffered minor injuries and were taken to the hospital.
Nobody was unaccounted for, but a dive team was doing a final sweep, just in case.
Anybody still in the water will probably not be rescued, officials said.
Photographs showed a wide gap in the northern side of the bridge, with significant debris in the water.
There were no indications as of 9 p.m. of what may have caused the collapse, which backed traffic up for miles.
The bridge, built in 1955, has a sufficiency rating of 57.4 out of 100, according to federal records. That is well below the statewide average rating of 80, according to an Associated Press analysis of federal data, but 759 bridges in the state have a lower sufficiency score.
According to a 2012 Skagit County Public Works Department, 42 of the county's 108 bridges that are 50 years or older. The document says eight of the bridges are more than 70 years old and two are over 80.
Washington state was given a C in the American Society of Civil Engineers' 2013 infrastructure report card and a C- when it came to the state's bridges. The group said more than a quarter of Washington's 7,840 bridges are considered structurally deficient or functionally obsolete.