Started by a lightning strike, the fire was first reported on July 29, 2021 on McFarland Ridge south of Highway 36.

[4] Red Flag Warnings were put in place for the weekend with potential to aid the fire's growth.

[9] By August 3, the south side of the fire crossed Hayfork Creek and was burning in both Trinity and Shasta Counties.

[1] Smoke from the fire was carried into the Sacramento Valley and San Francisco Bay Area starting July 6.

On August 16, strong west-northwest winds pushed the fire into Tehama County, adding an additional 40,000 acres over the course of the next two days.

Smoke from the McFarland Fire impacted the air quality in Hayfork, Yolla Bolla Middle Eel Wilderness, Sacramento Valley and the San Francisco Bay Area.

[13] This article incorporates public domain material from websites or documents of the United States Forest Service.