Walls of wind-whipped flames running all but unchecked consumed hundreds of homes across tinder-dry Southern California on Tuesday, and authorities ordered people in more than 350,000 homes to flee the fires.The blazes bedeviled firefighters as fires roared from mountain passes to the edges of the state's celebrated coastline, spreading so quickly that even hotels serving as temporary shelters for evacuees had to be evacuated. Two people have been killed.By day three, more than a dozen wildfires had burned more than 1,300 homes and businesses, and the destruction may only be the start for the region. With temperatures rising and wind gusts remaining fierce, the flames were proving nearly impossible to fight.Marilee Bishop of Running Springs and her 10 year-old-daughter, Erica, rubbed their red eyes Tuesday morning as they woke up in a Wal-Mart parking lot where they spent the night after being forced to leave their home."No one ever expects something like this to happen to them," said Bishop, as thick smoke rose in the skies behind her.Since they began Sunday, the fires have burned at least 373,000 acres, or 583 square miles -- an area the size of the Hawaiian island of Oahu. Affected areas stretched from north of Santa Barbara more than 200 miles south into Mexico. Flames climbed halfway toward the Nevada line, chewing through chunks of seven counties and devastating numerous communities.At least 346,000 homes in San Diego County alone -- roughly one in three, according to census data -- were ordered to evacuate, sheriff's officials said. State officials were still struggling to estimate how many people had fled.As the fires spread, most out of control, smaller blazes merged into larger, more fearsome ones. Evacuations were being announced in one community after another as firefighters found themselves overwhelmed by gale-force Santa Ana winds, some gusting to 70 mph.Authorities hadn't even begun to estimate the dollar value of the damage in some of the hardest-hit areas. A fire that struck Ramona, a city outside San Diego, had destroyed 650 structures. A blaze near Fallbrook, on the eastern edge of Camp Pendleton, wiped out another 500, or three buildings for every one firefighter allocated to it. And 200 more buildings burned in a fire just south of Potrero, across from the Mexican city of Tecate.President Bush declared a federal emergency for seven counties, a move that will speed disaster-relief efforts, and planned to visit the region Thursday, White House press secretary Dana Perino said."All of us across this nation are concerned for the families who have lost their homes and the many families who have been evacuated from their homes," Bush said. "We send the help of the federal government."Fire crews and fleeing residents described desperate conditions that were sure to get worse. Temperatures across Southern California were about 10 degrees above average and were expected to approach 100 degrees Tuesday in Orange and San Diego counties.Deputies arrested two men for looting in the community of Ramona, and there were a handful of other looting cases reported, San Diego Sheriff's Lt. Mike McClain said.The fires were exploding and shooting embers in all directions, preventing crews from forming traditional fire lines and severely limiting aerial bombardment, officials said."Lifesaving is our priority. Getting people out from in front of the fire -- those have been our priorities," said Capt. Don Camp, a spokesman for the California Department of Forestry and Fire Protection.Thousands of residents sought shelter at fairgrounds, schools and community centers. The largest gathering was at Qualcomm Stadium in San Diego, where up to 10,000 evacuees anxiously watched the stadium's television sets, hoping for a glimpse of their neighborhood on the local news. San Diego Mayor Jerry Sanders pleaded for donations of blankets, cots, pillows and food for the people staying there, and officials said more people were expected to arrive Tuesday.The wildfires claimed at least two lives. An unidentified civilian died of burns in a fire in Santa Clarita, in northern Los Angeles County, U.S. Forest Service spokesman Jay Nichols said. Another man, Thomas Varshock, 52, was found dead Sunday.Overall, 45 people have been injured, 16 of them firefighters.A dozen firefighters battling blazes in Orange County had to deploy emergency shelters, a last resort when they are surrounded by flames, Orange County Fire Authority Chief Chip Prather said."They should not have had to do that," he said, complaining that quicker air support from the state might have snuffed those blazes before they blew up. "If we'd had the resources earlier to take care of those lines with hand crews, we wouldn't have been in that situation."In San Diego County, public schools were closed, as were campuses at the University of California, San Diego and San Diego State University.US Airways said it would waive some fees for customers traveling to or from Southern California who need to change their flights because of the fires.The scope of the infernos was immense and was reminiscent of the blazes that tore through Southern California four years ago this month, killing 22 and destroying 3,640 homes.The fires have been made worse by fierce Santa Ana winds. The winds -- which sweep through Southern California's canyons in fall and winter -- are stronger than normal, turning already parched scrubland into tinder. They generated walls of flame that bore down on housing developments in a wide swath.East of Los Angeles, a fire destroyed at least 160 homes in the Lake Arrowhead area, the same mountain resort community where hundreds of homes were lost four years earlier. Officials said at least 100 more homes were destroyed Tuesday in the mountain community of Running Springs, not far away."It's just sad when you see that," Gov. Arnold Schwarzenegger said at a news conference after touring the area. "We have to do everything that we can to help these people ... to help them get back on their feet as quickly as possible."