A fourth threat is also emerging: Drones.
Occasionally aircraft have been grounded by people flying drones, with a $75,000 reward now offered for the apprehension of anyone irresponsible enough to do so.
One four-foot drone shut down evening operations over the Lake Fire, which burned an additional 3.5 square miles overnight Wednesday, KTLA news reported.
“Low-flying air tankers cannot share the sky with drones because the small aircraft can be sucked into jet engines, causing the engines to fail and the planes to crash,” said a plea from the San Bernadino County Commissioners.
“We don’t want to deal with unknown aircraft in our airspace,” Mike Eaton, forest aviation officer for the San Bernardino National Forest, told KTLA TV. “They’ve got enough on their mind already … difficult terrain, difficult weather, winds and other things. They don’t need to be worrying about model airplanes or drones.”
“If you fly, we can’t,” Eaton told KTLA. “It’s breaking the law.”
A second drone was also spotted Wednesday by a firefighting pilot returning from a mission, he said.
Facebook and Twitter are filled with alarmed comments from residents. “This is crazy how fast it has spread,” said a commenter on the Facebook page of CalFire, identifying herself as Oona Montgomery. “Scary.
“Holy crap, my worst nightmare. Please by safe … everyone,” wrote Adrinee Bond Vandewiele.
Towns near the fires have been entirely or partially evacuated, with people on notice to expect further evacuations.
The largest blaze is a rapid-moving fire in Lake County, 130 miles north of San Francisco, that has burned some 13 square miles, according to the Associated Press.
The Napa Valley has also been hard hit, burning over 12 acres during the course of the past week. A 265 acre fire is raging some 20 miles from the entrance to Yosemite National Park, which officials reported was only 5 % contained last night.
Some of the blazes were man made, including one in Bass Lake, where a boy reportedly admitted starting the fire by playing with a lighter to burn pine needles. Officials say he may face criminal charges.
Others have been started by lightning strikes, officials reported.
Below is a CalFire map that is regularly updated.