New concerns were developing at the explosive Caldor Fire southwest of Lake Tahoe, the famed alpine lake straddling the California-Nevada state line and surrounded by peaks of the Sierra Nevada and resort communities.
The Caldor Fire, just 9% contained, has become the nation's number one priority for firefighting resources, said Chief Thom Porter, director of the California Department of Forestry and Fire Protection.
"It is knocking on the door to the Lake Tahoe basin," Porter said. "We have all efforts in place to keep it out of the basin but we do need to also be aware that is a possibility based on the way the fires have been burning."
Porter said he personally did not believe the fire would get into the basin but that he could be proved wrong.
The Caldor Fire has incinerated nearly 118,000 acres, or 184 square miles, of El Dorado National Forest and continuing assessments showed 721 structures destroyed, including 455 homes. More than 17,000 structures were still under threat, Cal Fire said.
More than 13,500 firefighters were working Monday to contain a dozen large California wildfires that have destroyed hundreds of homes and forced thousands of people to flee to safety.
After an extensive review of fire damage Monday, Gov. Gavin Newsom requested a presidential major disaster declaration for eight counties, Mark Ghilarducci, director of the California Office of Emergency Services, told a briefing near Sacramento.
If approved, the declaration would provide a wide range of assistance including housing, food aid, unemployment and governmental emergency costs, Ghilarducci said.
Nearly 43,000 Californians were under under evacuation orders and more than 500 households were in shelters, he said.
To the north, containment increased to 41% at the Dixie Fire, which has burned more than 731,000 acres, or about 1,142 square miles, in the northern Sierra Nevada and southern Cascades. Ongoing assessments showed 1,262 structures destroyed, including 679 single-family homes, Cal Fire said. Nearly 12,000 structures remained threatened.
In Nevada, public schools in the Reno-Sparks area and parts of Lake Tahoe were closed Monday due to wildfire smoke, affecting 67,000 students.
In Northern California, where most of the blazes are burning, there were no red flag warnings for critical conditions but the seven-day outlook called for moderate fire danger.