Calmer winds helped crews fighting a massive wildfire today that killed four firefighters and critically injured a fifth, while investigators searched for the arsonist who set the blaze roaring through the canyons of Southern California.

FIRE crews yesterday struggled to protect homes from a wind-whipped wildfire that trapped and killed four firefighters in a wall of flames as it raced across almost 38 square miles in southern California.

The first major US wildfire of the summer raced across more than 5,500 acres of tinder-dry desert brush, destroying at least seven homes, threatening hundreds of others and sending residents of Morongo Valley fleeing for their lives.

Tens of thousands of people fled mountain communities in southern California as frantic residents raced to avoid the state’s deadliest wildfires in more than a decade.

A wildfire raging east of Los Angeles overran two fire engine crews, burning three people and shutting down the main road between Southern California and Las Vegas.