FRESNO (CBS/AP) — Campgrounds were evacuated near a Central California wildfire that has chewed through more than 2 square miles of dry timber in Sierra National Forest, one of several blazes burning across the state on Monday.

The fire in a rural area of Madera County, north of Fresno, was just 5 percent contained late Sunday. Officials said about 450 structures in the tiny wooded communities of Bass Lake and Cascadel Woods were threatened and residents were notified to prepare to evacuate at a moment’s notice. The cause of the fire that broke out Saturday was under investigation.

To the north, four firefighters were burned Sunday while battling a wildfire that threatens 150 homes in the Sierra Nevada foothills, about 45 miles northeast of Sacramento.

The four were injured at around 5 p.m. as they fought the hot, active northern end of the 2-square-mile blaze. They were airlifted to UC Davis Medical Center in Sacramento, state fire spokesman Daniel Berlant said.

Two state firefighters and a U.S. Forest Service member were expected to be treated and released. The fourth, also a federal firefighter, had serious but non-life threatening injuries, Berlant said.

He had no details of how the firefighters were injured but said a fire engine was damaged by the fire that erupted Saturday. About 1,100 firefighters, aided by a DC-10 and other aircraft, battled the fire but it was only 15 percent contained Sunday night.

Some 30 to 40 homes in foothill communities, including one belonging to Berlant’s parents, were under mandatory evacuation, but the flames placed up to 200 homes at risk, Berlant said.

“Many of the people live off the grid, they want to be left alone, and they have trees all over the place” which makes it harder to protect them from fire, Berlant said.

Temperatures for Monday could start rising toward triple digits and winds could shift and drive flames back south. If that happens, hundreds and hundreds of additional homes could be threatened, Berlant said.

Crews are battling about a dozen major blazes statewide. Since Jan. 1, firefighters have responded to some 1,200 more blazes than they typically would face for the period and “as we continue to get deeper into the summer, conditions are only going to be drier,” Berlant said.

Meanwhile, firefighters gained ground against a wildfire near Napa Valley wine country, and on Monday that fire was 70 percent contained.

The Napa-area blaze has burned more than 10 square miles of drought-parched countryside near Lake Berryessa, about 45 miles east of wine country

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