The blaze, known as the McKinney Fire, scorched more than 51,000 acres on Sunday afternoon, according to CAL FIRE. It is contained at 0%.
Governor Gavin Newsom proclaimed a emergency state Saturday for Siskiyou County, saying the fire threatened critical infrastructure and forced nearly 2,000 residents to flee their homes.

The McKinney Fire began Friday in Siskiyou County, near the California-Oregon border, about four hours north of Sacramento. The Klamath National Forest lists the cause of the fire as under investigation. Siskiyou County has a population of approximately 44,000, according to the US Census Bureau.

A mandatory evacuation order was announced Saturday for parts of Siskiyou County, according to Siskiyou County Sheriff’s Office. Residents of the evacuation zone are asked to “please leave immediately”.
About 60 people were evacuated from the Pacific Crest Trail on Saturday due to the fire at McKinney, the Jackson County Sheriff’s Office in Oregon said on his verified Facebook page, noting that the hikers were rescued from the “California side of the Red Buttes desert”. The Pacific Crest Trail stretches from the Mexican border through California, Oregon and Washington into Canada, according to the forest service.
A red flag warning, which indicates dangerous fire conditions, is in effect for the area until Sunday evening, according to the National Weather Service. “Heavy lightning” is expected through Monday, along with scattered thunderstorms, which “could help spread the fire” but could also bring “locally significant wet rain” to some areas, the weather service said.

Firefighters were forced to change their tactics “from an offensive perimeter control effort” to a more defensive posture to assist with evacuations on Saturday morning, an InciWeb report notes.

According to the governor’s office, two other fires burning in Siskiyou County — the China 2 and Evans fires — merged and together burned more than 300 acres, prompting evacuation warnings for more than 200 residents.

The state of emergency is intended to free up state resources and allow firefighters from other states to help crews fight California fires, according to the governor’s office.

CNN’s Michelle Watson and David Williams contributed to this report.