SAN DIEGO - At least 16 wind-driven wildfires burned from the Mexican border to areas north of Los Angeles on Tuesday, forcing more than half a million people from their homes and claiming a second life on the third day of fire calamity.

San Diego County faced the most dire situation as flames raced unchecked, with 500,000 people now ordered to evacuate their homes, county supervisor Ron Roberts said. At least 1,250 homes were destroyed.

Another person died on Tuesday from burns in a fire north of Los Angeles, after the first death reported on Sunday some 150 miles (241 km) away near San Diego.

A state official told Reuters that the fires have likely caused several hundred million dollars of damage.

Gov. Arnold Schwarzenegger said 6,800 homes were threatened statewide and 18 firefighters were injured among the 6,000 manning the fire lines.

"We have had three things come together -- very dry areas, very hot weather and a lot of wind. This makes the perfect storm for fire," Schwarzenegger said at Lake Arrowhead, where two blazes had destroyed 240 homes and threatened two mountain communities.

Officials said there was little they could do to stop one fire if it reached the tiny hamlet of Smiley and that Running Springs was also in imminent danger.

President George W. Bush early on Tuesday declared an emergency in the state and authorized the Federal Emergency Management Agency to coordinate disaster relief in the seven affected counties.

Bush planned to visit the fire-stricken area on Thursday to get a close look at the damage and emergency efforts, the White House said.

Hot Santa Ana winds continued to gust in from the deserts at up to 65 mph (105 kph) on Tuesday and high wind warnings remained in effect for most of the region until Wednesday afternoon.

More than 300,000 acres (120,000 hectares) have burned, an area about twice the size of Chicago, stretching fire crews and state emergency services to their limits. But federal authorities said the emergency response was well under control.

HUMANS, HORSES, PETS

Meanwhile San Diego Mayor Jerry Sanders told people to "stay at home, stay off the freeways" so fire crews and evacuees could keep moving as the winds changed course.

New fires erupted on the Marine base of Camp Pendleton, one of the largest in the United States and home to 60,000 people in the northern part of the county, base officials said.

San Diego officials said people were cooperating and evacuating quickly, resulting in minimal loss of life, amid memories of the last major fire in 2003 when 15 people died and 5,000 buildings were destroyed.

"We've been through this before," said Sonya Johnson, 43, who evacuated with her husband and young son. "I am sitting here thinking about the things I didn't take, like pictures and our will."

Some 8,000 people, including senior citizens from nursing homes, went to the Qualcomm stadium, where football San Diego Chargers play, or to the Del Mar Fairgrounds, famed for its horse racing track. Thousands of horses and family pets were also accommodated.

Evacuees at Qualcomm said the operation was well organized and clean, a sharp contrast to the chaos at New Orleans' Superdome, which was used as a refuge after Hurricane Katrina flooded the city in 2005.

"Unlike previous natural disasters, this time everybody has responded very quickly," Schwarzenegger said, adding that the refugees at Qualcomm were "being treated very well."

In the celebrity enclave of Malibu, north of Los Angeles, where the first fire raged early Sunday, there was no active burning and 500 of the 1,400 firefighters were dispatched to other areas.

The state insurance commissioner, Steve Poizner, told Reuters that the fires have likely caused several hundred million dollars worth of damage to homes and businesses.

"This is just a terrible disaster; it's going to be one of the worst ever," Poizner said.