21 cars were involved in a large-scale crash early Monday just south of the King-Pierce County line near Seattle, Washington. Dashcam video shows the pileup on Interstate 5 as it unfolds.

The Washington State Patrol reported receiving a report of a 10-car crash caused by debris on the road at 5:05 a.m. By the time all was said and done, it had escalated to a 21-vehicle pileup.

The 21-car pileup began with debris on the roadway and escalated from there

Trooper Cameron Watts reported that the accidents were initially caused by debris on the roadway, according to KOMO News. However, foggy conditions and blocked lanes left drivers with nowhere to go, and things “quickly escalated.”

Watts said multiple cars with flat tires were pulled over on the road’s shoulders until tow trucks arrived. He also reported that most collisions involved cars hitting debris or minor car-to-car crashes. The debris on the roadway was a car part, “such as a muffler or bumper,” from a previous collision that occurred just before 5 a.m.

KGW News reported that 11 cars sustained damage from impacting other vehicles, while 10 were damaged by the debris. Amazingly, only one person needed to be taken to a hospital. They were transported to St. Joseph Medical Center in Tacoma. Three others were reportedly injured but did not require transport for medical care.

Backup from the pileup extended for miles as traffic waited for the accident scene to be cleared. All of the lanes were eventually reopened a little before 9 a.m.