A motorcycle sideswiped a car on Interstate 5 in Everett, critically injuring the rider who was thrown from the bike and creating hourslong delays during Friday night’s commute, authorities said.

The motorcyclist was driving “fairly erratically” on an I-5 northbound lane before crossing into another lane around 3:15 p.m., and crashing into a white BMW just north of 128th Street, Washington State Patrol Trooper Heather Axtman said.

The motorcyclist, only identified as in their 60s, sustained “serious, life-threatening” injuries and was transported to an Everett hospital in critical condition, she said. The BMW driver was not injured.

The right two northbound lanes on I-5 were temporarily blocked, but reopened around 5:30 p.m., Axtman said.

“There’s residual backup,” she said around 6 p.m. Friday. “Horrible backup potentially all the way to Mountlake Terrace.”

According to a tweet from the Washington State Department of Transportation around 5:30 p.m., a “long backup to Shoreline will stick around for a while longer.”

Axtman cautioned drivers to expect delays for the next few hours.

No further information about the motorcyclist or the crash was immediately available.