COBB, Calif. (AP) — Explosive fires are raging across California, causing people to flee their homes and burning a broad swath of land.

By:David McNew/Getty Images News

One wildfire spread to several rural communities in Northern California, charring nearly 40 square miles in several hours and forcing the evacuation of thousands of people. One of the blazes sent four firefighters to the hospital with second-degree burns.

The fire erupted in Lake County, about 100 miles north of San Francisco, Saturday afternoon and rapidly chewed through brush and trees parched from several years of drought. That's according to the California Department of Forestry and Fire Protection. An unconfirmed number of structures were destroyed. Entire towns as well as residents along a 35-mile stretch of highway were evacuated.

Department spokesman Daniel Berlant said the firefighters, all members of a helicopter crew, were airlifted to a hospital burn unit, where they were listed in stable condition.

To the east, firefighters battled a blaze about 70 miles southeast of Sacramento that exploded to more than 101 square miles in four days, turning the grassy, tree-studded Sierra Nevada foothills an eerie white. That fire, which broke out Wednesday, has destroyed at least 86 homes and 51 outbuildings, and is threatening thousands more.