SEQUOIA NATIONAL PARK — Fire crews moved to ramp up the battle Thursday against two expanding forest fires threatening Sequoia National Park’s giant sequoia trees and infrastructure.

The Colony and Paradise fires, ignited by lightning strikes last week, covered about 14 square miles in the steep Sierra Nevada. There is 0% containment.

More than 300 firefighters were on the lines, aided by helicopters and air tankers when smoke conditions allowed. On Thursday, a national interagency management team will take over the fires, being managed collectively as the KNP complex, and even resources are expected, said Mark Ruggiero, fire information officer for Sequoia and Kings Canyon national parks.

Evacuation Orders, Air Quality

The Paradise Fire has grown to the west, prompting the Tulare County Sheriff’s Office to issue a mandatory evacuation order for part of the community of Three Rivers. The area of Three Rivers under mandatory evacuation is the Mineral King Road in its entirety, areas along Sierra King Drive, Crest Lane, Hammond Drive, and Oak Grove Drive, and areas along Highway 198 from the intersection with Mineral King Road to the Sequoia National Park entrance station.

The latest evacuation order information is available at this link.

Air quality is seriously affected in Three Rivers, officials said. Particulate matter readings have been in the “hazardous” range for much of the day. Communities further from the parks are also feeling air quality impacts. Track your local air quality at this link.

Colony Fire Threatens Giant Forest

The Colony Fire was a threat to Giant Forest, home to more than 2,000 sequoias, but not imminently, said Mark Ruggiero, fire information officer for Sequoia and Kings Canyon national parks.

The fires are among the latest in a long summer of blazes that have scorched more than 3,500 square miles in California, destroying hundreds of homes.

Sequoia National Park has been closed and its headquarters and resident employees have been evacuated, along with a portion of the community of Three Rivers outside the entrance.

The park’s historic wooden entrance sign dating to 1935 was covered in fire-resistant wrapping, and hoses were in place at the headquarters area for structure protection.

Previous Prescribed Burns Might Help

A 50-year history of using prescribed burns to remove other types of trees and vegetation in the park’s sequoia groves was expected to help the giants survive by lessening the impact if flames reach them, Ruggiero said.

Giant sequoias, some thousands of years old, live on the western flank of the Sierra. They are adapted to fire, which can help them to thrive by releasing seeds from their cones and creating clearings that allow young sequoias to grow.

But Ruggiero noted that the extraordinary intensity of fires in current climate conditions can overwhelm sequoias, a scenario that played out when the 2020 Castle Fire killed many trees in the region.

Castle Fire Killed as Many as 10,600 Large Sequoias

Studies estimate that 7,500 to 10,600 large sequoias were killed by that fire, along with many of other sizes, according to the National Park Service.

The Colony Fire also poses a broader danger because it is burning at an elevation of the central Sierra where there are 280 million pines and other types of trees that have been killed by drought and bark beetles, Ruggiero said.

“The Colony Fire specifically is burning in a really bad spot … where these trees are like jackstraws and it’s difficult to put fire personnel into some of these areas because of that,” he said.

Other Fire Updates

Elsewhere, two California fires that have caused extensive destruction in the northern Sierra and the southern Cascades were not growing.

The state’s second-largest fire on record, the Dixie Fire, was 86% contained after burning 1,500 square miles in the northern Sierra and southern Cascades region. Near Lake Tahoe, containment of the 342-square-mile Caldor Fire increased to 71%.

North of San Francisco, a 20-year-old Ukiah man was arrested Tuesday and jailed on suspicion of starting the Hopkins Fire in Mendocino County, the California Department of Forestry and Fire Protection said in a statement. The fire that sparked Sunday north of Ukiah charred 257 acres, destroyed homes and forced evacuations.

(GV Wire contributed to this article.)