Blazes raging in forests and woodlands across California have taken the life of a firefighter, burned two dozen homes and forced thousands of people to flee as crews continue to battle the flames from the air and the ground.

Twenty-one large fires, many sparked by lightning strikes, were burning across Northern California on Saturday, said Daniel Berlant, spokesman for the state Department of Forestry and Fire Protection. About 8,000 firefighters were working to subdue them, something made incredibly difficult by several years of drought that have dried out California.

The fires prompted Gov. Jerry Brown to declare a state of emergency for California and activate the California National Guard to help with disaster recovery.

Berlant said the danger was expected to continue through the weekend, with more thunderstorms expected.