What Is 2013 I-5 Skagit River Bridge collapse

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Last updated: April 15, 2026

Quick Answer: The I-5 Skagit River Bridge in Washington collapsed on May 23, 2013, when an oversized truck struck critical overhead supports, causing a 40-foot section to fall into the river; no fatalities occurred, but two vehicles fell into the water.

Key Facts

Collapse occurred on May 23, 2013 at approximately 7:00 PM.
No fatalities, but three people were injured and rescued from the river.
The bridge was a fracture-critical steel truss design, meaning failure of one component could cause collapse.
An oversized load with a height of 15 feet 6 inches struck critical girders.
The bridge was reopened on June 19, 2013, just 27 days after the collapse.

Overview

The I-5 Skagit River Bridge collapse was a significant infrastructure failure that occurred in northern Washington State on May 23, 2013. The incident disrupted a major north-south transportation corridor along Interstate 5, which connects Washington to Canada.

Although no lives were lost, the collapse highlighted vulnerabilities in aging U.S. bridge designs and raised concerns about the regulation of oversized vehicle loads. Emergency response teams quickly rescued three people from the Skagit River after two vehicles fell during the collapse.

Date of collapse: The bridge failed on May 23, 2013, at approximately 7:00 PM Pacific Time, following a collision with an oversized truck.
Location: The bridge spanned the Skagit River near Mount Vernon, Washington, about 70 miles north of Seattle.
Design type: It was a fracture-critical steel truss bridge, meaning the failure of a single structural member could lead to partial collapse.
Immediate cause: An oversized truck carrying an industrial module struck overhead support beams, dislodging critical components and leading to failure.
Recovery timeline: A temporary span was installed quickly, and the bridge was fully reopened on June 19, 2013, just 27 days after the incident.

How It Works

The collapse resulted from a combination of infrastructure design limitations and transportation oversight failures. Understanding how such an event could occur requires examining the engineering and regulatory factors involved.

Fracture-critical design: This type of bridge lacks redundancy; failure of one component can cause collapse, unlike modern designs with backup load paths.
Oversized load permits: The truck had a permit, but route surveying failed to account for clearance issues at this specific overpass.
Height clearance: The bridge had a 15-foot 5-inch vertical clearance, while the truck’s load was 15 feet 6 inches—just one inch too tall.
Structural impact: The truck struck two vertical cross-braces on the overhead truss, which were essential to the bridge’s stability.
Immediate failure: Within seconds of impact, the 40-foot central span collapsed into the Skagit River below.
Emergency response: Washington State Department of Transportation (WSDOT) and local agencies rescued all occupants within minutes using boats and helicopters.

Comparison at a Glance

The Skagit River Bridge collapse can be better understood by comparing it to other bridge failures in terms of cause, design, and response time.

Bridge Incident	Year	Primary Cause	Design Flaw	Recovery Time
Skagit River Bridge	2013	Oversized vehicle impact	Fracture-critical truss	27 days
I-35W Mississippi Bridge	2007	Design error in gusset plates	Under-engineered joints	13 months
Francis Scott Key Bridge (Baltimore)	2024	Ship collision	Non-fracture-critical	Est. years
Polcevera Viaduct (Morandi Bridge)	2018	Structural degradation	Prestressed concrete decay	Still under reconstruction
Dee Bridge	1847	Cast iron failure	Poor material choice	Months

This comparison shows that while the Skagit collapse was caused by external impact, its rapid repair was due to the relatively localized damage and availability of prefabricated components. Unlike the 2007 I-35W collapse, which required full reconstruction, the Skagit incident only needed a temporary span. The use of fracture-critical designs, however, remains a national concern, with over 600 similar bridges still in use across the U.S.

Why It Matters

The Skagit River Bridge collapse had lasting implications for infrastructure policy, transportation safety, and emergency preparedness across the United States.

National infrastructure awareness: The incident sparked renewed debate about the state of aging bridges and the need for federal investment.
Regulatory changes: Washington State reviewed its permitting process for oversized loads and improved route clearance databases.
Engineering standards: The event accelerated efforts to retrofit or replace fracture-critical bridges nationwide.
Emergency response model: The rapid rescue and repair served as a case study for disaster management agencies.
Public safety: It highlighted how small clearance miscalculations can lead to major infrastructure failures.
Transportation economics: The closure disrupted thousands of daily commuters and freight shipments, costing millions in delays.

The collapse ultimately served as a wake-up call, emphasizing the need for modernized infrastructure, better coordination between transportation departments, and improved oversight of commercial vehicle routes.