A fast-moving brush fire dubbed the Post Fire scorched more than 100 acres in Gorman Sunday night, while parts of northbound Interstate 5 and Highway 138 remained closed Monday morning.

A flyover conducted Monday morning showed that while the fire was thought to have burned approximately 200 acres, forward progress had been stopped at 120 acres, with 35% containment, according to Los Angeles County Fire Department Spokesman Chris Thomas.

L.A. County Fire Department personnel first responded to reports of a brush fire near Gorman Post Road and northbound Interstate 5, just north of Highway 138, around 7 p.m. Sunday, according to Supervisor Michael Pittman.

Firefighters from Kern County and the Angeles National Forest responded with a first alarm assignment, along with a number of water-dropping helicopters and tankers.

What began as a quarter acre of brush burning quickly grew to four acres before it was halted at 120 acres around 10:30 p.m., burning down only one vacant, abandoned structure, per fire officials.

The Post Fire in Gorman burned 120 acres and shut down parts of Interstate 5 as firefighters worked to contain the blaze on Sunday, Aug. 2, 2020. | Photo: Courtesy of CHP Fort Tejon.

California Highway Patrol officers issued a SigAlert about the Post Fire around 9:30 p.m., closing northbound Interstate 5, along with Highway 138. Southbound Interstate 5 also received delays as CHP officers worked to allow fire trucks access to the blaze.

As of 3 a.m., several lanes of northbound Interstate 5, just north of Highway 138, remained closed, while westbound Highway 138 was closed at Gorman Post Road, according to Officer Tony Polizzi.

Units remained on the scene overnight in “overhaul mode,” as they worked through the night to handle Post Fire hotspots, according to a social media post from the fire department.

The cause of the fire remains under investigation.