Thousands of people have been told to leave their homes as a wildfire burning Sunday in thick forest threatened rural communities in far Northern California.

The fire that sparked around 11:30 a.m. Saturday has destroyed four homes and consumed nearly 11 square miles near the towns of Manton, Shingleton, and Viola, fire spokesman Daniel Berlant said. About 3,500 homes spread out across a rural area along the border of Tehama and Shasta counties are threatened, he said.

"A good majority are immediately threatened and a good number are in the path of the fire," Berlant said Sunday. "We will be battling it hard today to protect as many of those homes as possible."

The cause of the fire has not been determined, but officials said it started after a series of lightning strikes in the area. The wildfire is zero percent contained.

The fire, burning in a rugged area of thick forests about 170 miles north of Sacramento, is one of handful of new fires burning in Northern California.

Another wildfire that started Saturday has consumed about 1.5 square miles east of the Mendocino County community of Covelo. The blaze, which was sparked by lightning, is burning in a remote area of thick timber and rugged terrain, making it difficult for fire crews to get to.

A third new fire has scorched about a half square mile in a remote area of Shasta County.