Three helicopters from the Los Angeles County Fire Department Air Operations Section dropped water over the affected region, according to a post on the department’s official Twitter account.

No evacuation orders have been issued so far and no injuries have been reported. The cause of the fire has yet to be determined.

The blaze, dubbed the Equestrian Fire, first broke near the Jack Bones Equestrian Center in Castaic around 3:40 a.m. local time Monday and was at about five acres, KABC in Los Angeles reports.

The fire expanded to 20 acres by around 4:50 a.m. local time and burned power lines nearby, and at one point threatened the Peter J. Pitchess Detention Center, a men’s county jail facility, CBS Los Angeles reports.

Earlier on Monday, a supervisor with the LACFD noted: “It [the fire] has the potential to threaten nearby structures at the Wayside Facility,” according to the KHTS radio station based in Santa Clarita, around 30 miles north of downtown Los Angeles.

The fire was reported to have had a “moderate rate of spread” as of 4:30 a.m. Monday, KHTS reports.

Red Flag Warnings have been issued for parts of southwest California through Monday, with northerly winds gusting 40 to 60 miles per hour and shifting to the northeast on Monday, the National Weather Service (NWS) Los Angeles confirmed in a post on its official Twitter account.

“Red Flag Warnings indicate that there is the potential for rapid fire spread and extreme fire danger with fire ignitions. Residents are urged to be set to evacuate if told by emergency officials,” the NWS explains.

The strongest winds are expected in the mountain and foothill areas, while rapid warming and drying will take place Monday, with humidity levels dropping to about five to 15 percent, the NWS noted in the post.

“Elevated fire weather conditions” are expected on Tuesday, with breezy conditions, low humidity levels and hotter temperatures, the NWS warns.

On Friday, a four-acre brush fire was reported in the Sepulveda Basin in the San Fernando Valley region of Los Angeles County.

The fire, reported in the 6,000 block of North Woodley Avenue in the Van Nuys area, was said to have spread by 20 miles per hour winds, the Los Angeles Fire Department confirmed.

The fire was contained, with all flames extinguished by around 5 a.m. local time. No injuries or damages to structures were reported. Water-dropping helicopters were also used to assist ground crew who used heavy machinery to clear debris from the fire, CBS Los Angeles reported.