A 32-year-old man has been arrested on suspicion of starting the fires, including a blaze which threatened 600 homes in the San Jacinto Mountains, east of Los Angeles, according to state fire officials.
One of the fires which erupted on Wednesday afternoon quickly grew to seven and a half square miles after being fuelled by dry bushes and trees.
This resulted in around 12,000 people living in Idyllwild and the surrounding areas to be evacuated.
No injuries have been reported but several hundred people, as well as animals and children from summer camps, are currently staying in shelters.
Further north in the San Francisco Bay Area, at least one home burned in a fast-moving blaze in Clayton.
This is one of the many fires burning amid a statewide heat wave.
Over the past two weeks, the fires have burned through 60 square miles of timber in the steep terrain of Sierra Nevada just west of the park.
The fire is just 25 per cent contained.
More than 3,300 firefighters and 16 helicopters have been tackling the fire.
One firefighter was killed on July 14, while six others have been injured.
Where is Yosemite National Park?
Yosemite National Park is located in California’s Sierra Nevada mountains.
The park is famed for its ancient sequoia trees and for Tunnel View, where visitors can see the towering Bridalveil Fall and the granite cliffs of El Capitan and Half Dome.
Despite it being the height of tourist season, Yosemite Valley, a glacial valley in the heart of the national park, was closed on Wednesday afternoon as smoke spread from a fire in Sierra Nevada.
Officials clarified Yosemite wasn’t in danger from the fire, but crews needed to safeguard the area without having to deal with the traffic from millions of visitors.
The valley will be closed until at least Sunday, as well as the 20-mile stretch of the State Route 41 that leads into the area.
This has resulted in at least 1,000 campground and hotel bookings being cancelled.
The last time the valley was closed because of fire was in 1990.