Destruction and death are riding the wind again this autumn in Southern California.

It is the dread Santa Ana wind, moving down the canyons and through the gaps in the mountains, driving wildfires before it like a fiery torch.

The Santa Ana winds go back into California's blazing history. They always come in the fall and winter of the year. In Southern California, October is the cruelest month.

The worst disasters usually happened in this otherwise benign month.

Raymond Chandler, the celebrated mystery writer, mentioned the Santa Ana wind in his story "Red Wind," and so did Joan Didion in her books about California. The Santa Ana season produces a vague unease, a sense of something evil in the air.

"One of those hot dry Santa Anas that come down through the mountain passes and curl your hair and make your nerves jump and your skin itch," Chandler wrote. "On nights like that every booze party ends in a fight ... anything can happen."

The explanation for the Santa Ana is simple: high atmospheric pressure in the Great Basin, in Nevada and Utah, the dry heart of the West. On the coast, the atmospheric pressure is lower. The wind always blows from high pressure to low.

But in this case, said meteorologist Jan Null, an expert on the climate of the West, the wind blows downhill, toward the ocean, being compressed as it moves, heating up as it goes, blowing toward the coast.

"It dries out as it moves, becoming a very dry wind," Null said.

At its worst, the Santa Ana moves through the passes at 70, 80, sometimes 100 mph. It is worst in the fall, when the land is dried out after the long, rainless Southern California summer.

This year has been one of the driest ever recorded in the Los Angeles basin. "An exceptionally dry winter," said Warren Brier of the National Weather Service. "The driest in Los Angeles in 100 years."

Then the table is set for disaster - a hot, dry wind blowing over hills, single-digit humidity, and valleys loaded with brush like chamise and chaparral. Between the brushy hills are the cities and towns that ring the coast.

This fall, the brush has been dried by drought, just waiting for a spark.

In 2003, the same conditions produced 15 huge fires that swept over the mountains behind San Diego and dropped ashes in the city's downtown. More than 1,000 square miles of land burned, 2,232 homes were lost and 14 people, including a Novato firefighter, were killed.

This one appears worse: Hundreds of thousands of people were evacuated by Tuesday, and hundreds of homes were lost. People in San Diego County were told not to go to work, and schools were closed. "I don't know anybody who wasn't affected," said Lynn Delgado, who had to leave her condo in San Diego's Mira Mesa district and take refuge in Point Loma on the coast.

Fire and Southern California are old partners, and the fear of fire goes back far into the region's history. The Spanish governor warned of wind and fire in a message in 1793.

By the turn of the 20th century, the winds that drove the fires had a name - Santa Ana, after the Santa Ana Canyon.

By 1901, the city fathers of Santa Ana, the Orange County seat, tried to have the name changed on grounds it was bad for business.

But nobody knows for sure the origin of the name, Null said. "Where the name comes from is really a mystery."

Some called it the devil wind - the satana, after the Spanish name for Satan.

In the Bay Area, the hot winds blowing from the hills to the ocean are called Diablo winds, after Mount Diablo. Diablo winds were the driving force for the East Bay Hills Fire in October 1991, which burned 3,354 buildings and killed 25 people.

In Santa Barbara, the wind is called the Sundowner, which drove the huge Painted Cave Fire in 1990, a blaze that jumped Highway 101 and devastated whole areas of the city.

In Colorado the wind is called a Chinook, blowing off the mountains. In France, it is a mistral, in Austria, the foehn, and in Libya, a hot wind is called a gibbh.

Is the wind made worse by climate change or global warming? Null, the meteorologist, thinks not. "We've had these firestorms in October for hundreds of years," he said. And California has suffered from periodic droughts in the past.

"The record dry year has just exacerbated the problem," he said.

As it turns out, Santa Ana winds are as Californian as warm days in winter, as earthquakes. It's the price people pay for living in a mild climate that can turn fierce with almost no warning.