MOUNT VERNON, Wash. -- An Interstate 5 bridge over a river 60 miles north of Seattle collapsed Thursday evening, dumping vehicles and people into the water.
A semi truck with an oversized load was seen striking beams on the north end of the bridge, which carries 71,000 vehicles a day.
"For reasons unknown at this point in time the semi struck the overhead of the bridge causing the collapse," WSP Chief John Batiste told an overnight news conference.
The truck made it off the bridge and the driver remained at the scene and cooperated with investigators. The bridge has a traffic clearance of 14 feet 6 inches.
The driver has been identified as a 42-year-old man from Alberta, Canada. He was driving for Mullen Trucking.
Washington Gov. Jay Inslee has declared a state of emergency in Skagit, Snohomish and Whatcom counties that surround the collapsed Interstate 5 bridge.
Inslee says it will cost $15 million to repair the Skagit River bridge. The federal government has already promised the state $1 million in emergency dollars to fix the Interstate 5 bridge.
Inslee says he talked to U.S. Transportation Secretary Ray LaHood is promising his full support to get Washington's main north-south roadway repaired as quickly as possible.
The four-lane bridge over the Skagit River collapsed about 7 p.m., Trooper Mark Francis said. Skagit County Sheriff's Department said three people - two men and one woman - were rescued from the water and transported to area hospitals. All three were reported in stable condition.
State authorities say there were no fatalities.
"I saw it. I was less than 50 feet away from the truck when it hit it," witness Dale Ogden told KING 5. "I had just passed it in the fast lane southbound and it had an oversized load. It was approximately 12 feet wide and over 14 feet tall. It was in the slow lane when I came by...I was behind the flag car and in front of the truck in the other lane and I saw the whip - normally tells you how high they can clear - start hitting the bridge. I looked in my rearview mirror knowing this was not going to turn out well."
"I saw the truck strike the right corner of the bridge. It almost tipped the truck over but it came back down. It tipped it up to about a 30 degree angle to the left and it came back down on its wheels and almost instantaneously behind that I saw girders falling in my rearview mirror."
Washington State Patrol is investigating the incident and is asking anyone who witnessed the truck hitting the bridge to contact them at 1-360-654-1204.
Xavier Grospe, 62, who lives near the river, said he could see three cars with what appeared to be one person per vehicle. The vehicles were sitting still in the water, partially submerged and partly above the waterline, and the apparent drivers were sitting either on top of the vehicles or on the edge of open windows.
Helicopter footage showed several rescue boats at the bridge collapse scene with several ambulances waiting on the shore. One rescue boat left the scene with one person strapped into a stretcher.
A damaged red car and a damaged pickup truck were visible in the water, which appeared so shallow it barely reached the top of the car's hood. Crowds of people lined the river and watched the scene unfold.
Skagit County Sheriff Will Reichardt said rescue crews were nearby when they got the call.
"It was very fortunate that we literally had our boat operator on duty in the water in the area when the call came in. We were in the water within a few minutes," said Reichardt.
Bridge listed as 'functionally obsolete'
The bridge is not considered structurally deficient but is listed as being "functionally obsolete" - a category meaning that their design is outdated, such as having narrow shoulders or low clearance underneath, according to a database compiled by the Federal Highway Administration.
The bridge was built in 1955 and 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 of functionally obsolete.