Much of the Grapevine was inaccessible for more than four hours Sunday night after a mudslide prompted the closure of about 35 miles of the northbound 5 Freeway, according to the California Highway Patrol.

The closure occurred around 7 p.m. after a mudslide a mile and a half north of Fort Tejon Road in Lebec, an unincorporated area in southwest Kern County, CHP Officer Bishop said.

Officials closed the northbound 5 Freeway between the mudslide’s location and Parker Road, in the Castaic Canyons area.

Crews worked to clear the area, and were able to reopen it before 11:30 p.m. thanks to the rain holding off, Caltrans tweeted.

Traffic was backed up about four miles before Parker Road prior to the reopening, according to SigAlert.com, and one driver who was stuck on the freeway told KTLA traffic was at a complete standstill.

A motorist who saw the mud flow described it as a heavy stream that included mud, “huge rocks” and tree limbs.

Alternative routes included taking the 14 Freeway to the 58, or heading west on State Route 126, Google Maps showed.

There was a 90 percent chance of precipitation in the Lebec area Sunday night, possibly bringing a tenth to a quarter of an inch of rain, the National Weather Service reported

The California Department of Public Transportation initially said a mudslide prompted a closure at Parker Road, but the CHP later clarified that the mudslide did not occur in that location.

KTLA’s Feven Kiflegiorgis contributed to this report.