Dome Fire in Yosemite determined to have been caused by abandoned campfire

The Dome Fire burning in California's Yosemite National Park was caused by an abandoned campfire, according to the U.S. Forest Service, as firefighters continue working to contain the blaze two weeks after it began.

The fire started Sept. 15 near Chilnualna Falls, north of Wawona, and has since grown to more than 5,400 acres. As of Tuesday night, the fire was 39% contained, according to officials.

The National Park Service had previously asked the public for information about possible unregulated campfires in the Chilnualna Falls area between Sept. 9 and Sept. 15. There has been no indication that investigators have identified the person who left the campfire.

Cooler temperatures, higher humidity and rocky terrain have helped firefighters strengthen containment lines and slow the fire's spread this week, officials said. There were no roads, buildings or utilities under immediate threat.

Smoke from the fire has continued to affect parts of Yosemite, although conditions have improved in some areas.

Two helicopter crew members died in a crash while fighting the Dome Fire in Mariposa County nearly a week and a half ago.

Yosemite National Park remains open, but several areas are closed because of the fire. Glacier Point Road remains closed, as are the Chilnualna Falls Trail and trails leading from the top of the falls toward Buena Vista and Crescent lakes. The Ostrander Lake Trail and areas south of it are also closed.