Heavy traffic along the northbound lanes of the 5 Freeway near the Grapevine has led to a 29-mile backup, authorities announced Wednesday.

“Two lanes are open Northbound, backup is up to 29 miles, approximately 1.5-to-2-hour delays,” Caltrans posted on X, formerly known as Twitter.

The significant backup was due to a big rig collision, which spilled debris across all lanes.

Crews are actively working to clean up the debris and all southbound lanes of the freeway remain open.

As of 6:30 p.m., Caltrans said that all lanes were open and clear, but that drivers should expect continued delays due to the approximately 30-mile backup.

The traffic nightmare comes one day before Thanksgiving, with many taking to the roads and skies to reach their destination.

About 4.6 million Southern California residents are expected to travel until Nov. 26, according to the Auto Club of Southern California.

Last year, a record 4.5 million people in the region traveled for the holiday — about 3% less than this year’s forecast.