As Hurricane Rita roared toward the Texas and Louisiana coasts early Friday, a bus carrying 43 elderly evacuees — and their oxygen tanks — from the Houston area caught fire on Interstate 45 near Dallas. As many as 24 people are feared dead.
"Deputies were unable to get everyone off the bus," Dallas County Sheriff's spokesman Sgt. Don Peritz told CBS radio station KRLD. "This is a tragic, tragic accident," Peritz added.
Meanwhile, Rita weakened slightly and was downgraded to a Category 3 hurricane, but was still considered dangerous.
CBS News has planned expanded coverage of Hurricane Rita this weekend. For details,
The bus was carrying 38 residents and six employees of the Brighton Gardens nursing home in Bellaire, Texas, according to Sunrise Senior Living, the McLean, Va., company that owns the center.
Authorities took the unusual step of moving the wreckage and continuing investigating at a remote location so the interstate could reopen for evacuees, Peritz said.
"We got in contact with Homeland Security in Washington, D.C. They are very concerned" about the highway backing up, Peritz said.
Friday morning Rita was a major Category 4 storm that spurred a traffic-snarled exodus toward higher ground and fears it could cripple the heart of the nation's petrochemical industry.
At 1 p.m. EDT, Rita was centered about 190 miles southeast of Galveston and 175 miles southeast of Port Arthur, and was moving to the northwest at nearly 10 mph. Its winds were near 125 mph. Forecasters expect landfall early Saturday morning near the southwest Louisiana and upper Texas coasts.
"I think I'm correct in saying it is the largest evacuation in Texas history," said Gov. Rick Perry.
The unprecedented flight from the flood-prone Houston area left clogged highways at a near standstill, frustrating hundreds of thousands of people whose cars and tempers were overheating.
Houston's airport looked like the days before Thanksgiving and Christmas, reports CBS News correspondent Peter King. Thousands without reservations waited for hours to learn they were out of luck.
And Friday morning, Houston officials urged those still in the city to stay put and ride out the storm.
The first rain bands were expected before nightfall Friday with the full fury of Rita expected into Saturday.
"We're going to see a storm surge of 15 to 20 feet and winds of over 100 mph," said CBS News meteorologist George Cullen. "This is a huge storm, so hurricane-force winds extend out almost 80 miles from the center and tropical storm-force winds extend out 200 miles from the center, so we're going to have major impacts all along that Texas Louisiana coastline."
Two communities that may bear the brunt of the storm are Beaumont, which is a petrochemical, shipbuilding and port city of about 114,000; and Port Arthur, a city of about 58,000 that's home to industries including oil, shrimping and crawfishing.
Texas officials scrambled to reroute several inbound highways to accommodate outbound traffic, but many people were waiting so long they ran out of gas and were forced to park.
"We know you're out there," Houston Mayor Bill White said of the congestion that extended well into Louisiana. "We understand there's been fuel shortages."
By Friday morning, the traffic was at least moving slowly, but was still backed up for about 100 miles.
"One of the big problems is the capacity upstream, the fact that people are stopping for gas slowing down things, pulling over to rest, getting something to eat," said Houston Police Chief Harold Hurtt Friday on CBS News' The Early Show. "Each time they take action, it has an adverse reaction on the traffic behind them."
Nearly 2 million people along the Texas and Louisiana coasts were urged to get out of the way of Rita, a storm that weakened Thursday from a top-of-the-scale Category 5 hurricane.
"Hopefully, we will get lucky and it goes into a part of Texas or Louisiana where there is not a lot of people or any buildings," Houston businessman Tillman Fertitta said.
Hurricane warnings were in effect from Port O'Connor, Texas, to Morgan City, La., and the National Hurricane Center forecast the storm would make landfall as a "dangerous hurricane of at least Category 3 intensity."
Tropical storm warnings also were in effect east and north to include New Orleans, still crippled by Hurricane Katrina.
Hurricane Rita's steady rains sent water pouring throughFriday, cascading into one of the city's lowest-lying neighborhoods in a devastating repeat of New Orleans' flooding nightmare.
"Our worst fears came true," said Maj. Barry Guidry of the Georgia National Guard.
The Texas and Louisiana coast is home to the nation's biggest concentration of oil refineries. Environmentalists warned of the possibility of a toxic spill from the 87 chemical plants and petroleum installations that represent more than one-fourth of U.S. refining capacity.
Petrochemical plants began shutting and hundreds of workers were evacuated from offshore oil rigs. Perry said state officials had been in contact with plants that are "taking appropriate procedures to safeguard their facilities."
The usually bustling tourist island of Galveston - rebuilt after as many as 12,000 people died in a 1900 hurricane - was all but abandoned, with at least 90 percent of its 58,000 residents cleared out.
The last major hurricane to strike the Houston area was Category-3 Alicia in 1983. It flooded downtown Houston, spawned 22 tornadoes and left 21 people dead. The U.S. mainland has not been hit by two Category 4 storms in the same year since 1915. Katrina came ashore Aug. 29 as a Category 4.
Even once the storm passes, the danger may not be over.
"It looks like this storm actually may stall out over northeastern Texas and basically sit there for a couple of days, and if that happens, we're going to see some areas along the western sections of Louisiana and the eastern areas of Texas get up to 20 inches of rain with massive flooding, almost what we saw four years ago in Houston when Tropical Storm Allison dumped over 25 inches of rain over the city," warned Cullen.