Southbound I-5 traffic was backed up for miles Thursday morning after a fatal predawn crash near the King-Pierce county line.

The Washington State Patrol closed all but one lane early Thursday while they investigated; all lanes reopened around 6:30 a.m.

One person involved in the two-vehicle collision died and another was arrested for investigation of driving while intoxicated, Washington State Patrol Trooper Johnna Batiste tweeted.

“Please slow down and be patient as we process this scene,” Batiste tweeted around 3 a.m.