The El Dorado County Sheriff’s Office reported on Saturday that deputies were called to Echo Summit, a mountain pass south of Lake Tahoe, in response to a wildland fire report.
When deputies arrived at the scene, firefighters directed them to a suspect who was still in the area.
A person of interest, named as Viola Liu, was found wearing a bikini and covered in scratches and soot.
Ms Lui, from Fremont, California, allegedly admitted to starting the fire which was “corroborated by other evidence in the investigation,” the sheriff said in a Facebook post.
She was arrested at the scene for arson, possession of a controlled substance, possession of drug paraphernalia, and resisting/obstructing a police officer.
After her arrest, Ms Liu was booked into the El Dorado County Jail.
As well as being deadly and destroying homes, fires also release carbon dioxide into the environment, according to the US Forest Service.
Fires pump millions of tons of planet-warming carbon dioxide into the atmosphere, and in turn exacerbating the high temperatures and dry conditions which make wildfires easier to start.
The arson occurred as California is battling the Dixie Fire, the state’s second-largest wildfire in history.
That fire, around 120 miles north, has forced thousands of residents to evacuate their homes, and smoke has led to dangerous air quality in neighbouring states.