The fire began Monday and moved quickly before receding, but continued to move in a southwest direction and had the potential to grow due to north winds and low humidity, the California Department of Forestry and Fire prevention said.
The fire is considered 5 percent contained. It broke out shortly after noon Monday and grew to 500 acres in its first hour, the Chico, Calif., Enterprise said.
More than 1,100 people are engaged in putting out the blaze, the Redding, Calif., Record-Searchlight reported.
The Morgan Fire in Contra Costa County, north of San Francisco, had burned about 1,500 acres as of Monday morning, but by the evening, it exploded to 4,000 acres, the San Jose (Calif.) Mercury News reported.
Fire officials in California said the Morgan fire nearly tripled in size in less than a day, but they are optimistic about an earlier-than-expected containment.
"The total acreage has gone up dramatically today," said David Shew, staff chief for Cal Fire. "It's turning into a more difficult fight than we thought yesterday but we're throwing more resources at it."
"The fire is staying where we want," he added, but "something could always go wrong."
The fire was about 20 percent contained Monday afternoon, NBC News reported.
About 100 homes and other structures had been evacuated in an area of Mount Diablo State Park where about 800 firefighters were battling the blaze. Only one far-flung outbuilding had been damaged, NBC News said.
One injury from the blaze was reported, but the cause and nature of the injury was unknown.
Shew said he expects the fire to be contained by Wednesday.
The fire, which started Sunday afternoon, was spreading thanks to low humidity and dry brush, he said.