On Thursday, May 23, 2013, about 7:05 p.m. Pacific daylight time, a 2010
Kenworth truck-tractor in combination with a 1997 Aspen flatbed semitrailer
hauling an oversize load (referred to here as "the oversize combination
vehicle") was traveling south on Interstate 5 (I-5) near Mount Vernon,
Washington. The oversize combination vehicle had a permit for the route of
travel and was being led by a pilot/escort vehicle, a 1997 Dodge Ram pickup
truck. As the oversize combination vehicle traveled across the I-5 bridge above
the Skagit River, the oversize load struck the bridge, damaging its structure.
The oversize combination vehicle continued to travel across the bridge and came
to a stop on I-5 south of the bridge.
As a result of contact damage to the bridge's truss structure, span 8 of the 12-span bridge collapsed into the Skagit River. Two passenger vehicles, a
southbound 2010 Dodge Ram pickup truck towing a Jayco travel-trailer and a
northbound 2013 Subaru XV Crosstrek, fell into the river. Two other vehicles
were damaged during the event: a 2000 Kenworth truck-tractor in combination with
a 1996 refrigerated semitrailer in the southbound passing lane made contact with
the oversize combination vehicle, and a southbound 1995 BMW 525i received
undercarriage damage. Eight vehicle occupants were involved in the bridge span
collapse; three received minor injuries and five were uninjured.