An air tanker being used to fight a wildfire burning in Yosemite National Park crashed on Tuesday, and there was no immediate word on the pilot, a spokesman for the California Department of Forestry and Fire Protection said.
Cal Fire spokesman Daniel Berlant said in a tweet that the plane went down near the so-called Dog Rock Fire and that the condition of the pilot was "undetermined."
There was no immediate word on the cause of the crash and it was not immediately clear if rescue crews had found the wreckage.
Cal Fire spokeswoman Lynne Tolmachoff said the pilot was believed to be the only person on board the Grumman S2T, a two-engine aircraft that had been deployed over the fire.
Authorities began searching for the plane after it could not be reached by tactical planes that had been in contact with it, said Tolmachoff.
The Dog Rock Fire, which erupted at about 2:45 p.m. local time near Yosemite's Arch Rock formation in the western portion of the park, prompted the evacuation of about 60 homes in the community of Foresta.
State officials have said this year's California fire season, which traditionally runs from May to October, was on track to be the most destructive on record, intensified at least in part by record drought.
Cal Fire has responded to over 5,150 wildfires already and October is when the state often experiences its largest blazes.
In 2012, a firefighting plane crashed on a forested mountainside in southwestern Utah while on a mission to drop chemical fire retardant on an 8,000-acre (3,238-hectare) blaze near the Nevada border.
Two crew members were killed in that crash.
(Reporting by Steve Gorman and Dan Whitcomb; Editing by Cynthia Johnston and Eric Walsh)