Flames whirled dangerously close to homes Tuesday as gusty Santa Ana winds sent the biggest of southern California's wildfires flaring in hilly brushlands on Los Angeles' northern edge and along subdivisions to the west.

Firefighters with hoses guarded houses as helicopters unleashed loads of water on hot spots of the more than 20-square-mile blaze charring slopes above the San Fernando Valley communities of Porter Ranch and Granada Hills.

Flames then pushed west to the rolling grasslands of Ventura County and made runs toward Simi Valley neighborhoods of modern homes defended by a broad firebreak, helicopters, airplanes and ground crews.

The fire is one of three major blazes that have burned more than 34 square miles of Southern California, destroyed dozens of homes and forced thousands of people to evacuate their homes this week. One man died in the flames, and a motorist was killed in a crash as a fire neared a freeway.