The I-5 bridge over the Skagit River in Washington before it collapsed. (wikimedia/Creative Commons)

The Seattle Times reported that three people were rescued alive from the water. The collapse was caused by a truck that hit a beam on the upper portion of the bridge, which was built in 1955.

KCAL 9 reported that only two cars plunged into the water. They also reported that traffic was backed up for a large distance.

The cause of the collapse is still unknown, but authorities are investigating whether an oversize load struck the bridge.

Reach Staff Reporter Max Schwartz here; follow him on Twitter here.