EVERETT — A person digging under Highway 529 created a hole in the road that caused crews to shut down northbound lanes Tuesday morning north of Everett.

Around 9 a.m., the state Department of Transportation fully closed the northbound lanes for emergency maintenance near East Marine View Drive.

It appeared the hole “formed on the road from an individual tunneling underneath,” according to the department. “Crews are repairing the damage.”

Traffic was diverted onto southbound Highway 529, as well as Everett Avenue.

It was unclear if authorities had identified the person suspected of digging the tunnel.

Responders got to work removing the damaged asphalt and cleaning the void, according to the department. They back-filled the hole with gravel and resurfaced the asphalt. After giving the asphalt time to cure, the highway was open by 3 p.m.

Since June, drivers had already been squeezed during their daily commute on the route, as Highway 529 dropped from four lanes to two in a $13.5 million project to update the Snohomish River and Steamboat Slough bridges.

In 2021, firefighters spent hours digging and searching inside a collapsed tunnel built underneath an I-5 off-ramp at Pacific Avenue and Walnut Street.

In that incident, Department of Transportation crews had been street cleaning at the on-ramp when they saw a man pop out of some bushes and run off. They discovered an uncovered, horizontal underpass that stretched almost 45 feet. Authorities feared a person could have been trapped inside, but found no one inside the tunnel.

Jonathan Tall: 425-339-3486; jonathan.tall@heraldnet.com; Twitter: @snocojon.