The one-timelost some of its steam before rumbling in from the Gulf of Mexico, weakening to a Category 2 storm at 5 a.m. PDT, but it still packed enough punch to cause widespread damage.
Officials across the region said the high winds had toppled trees, destroyed buildings and sparked numerous fires as it.
"We have trees across roads. In downtown we have observed several businesses totally destroyed," said Sulphur, La., police department spokesman George Mullican. "It's too dangerous to send anyone out right now because of the wind."
In Rita's path were many of the nation's largest refineries, but their fate was not yet known. One of the hardest hit cities was Beaumont, Texas, where the U.S. oil age began with the discovery of the Spindletop oil well in 1901.
The powerful storm knocked a huge container ship loose from its moorings in Lake Charles, La., and left more than half a million people without electricity.
"It's unbelievable," Lake Charles Police Chief Tommy Davis told a Louisiana television station. "There's going to be a lot of destruction out there."
A spectacular fire engulfed three buildings in Galveston's historic downtown and another building collapsed in the same area as Rita raked the island city.
Centerpoint Energy spokesman Floyd LeBlanc said at least 530,000 customers in Texas had no electricity.
The eye of the storm hit land in extreme southwestern Louisiana, a swampy, lightly populated area just east of Sabine Pass, Texas, the U.S. National Hurricane Center in Miami said.
Earlier in the week, Rita was a roaring Category 5 storm with 175 mph (281 kph) winds, but those dropped to 120 mph (193 kph) at landfall, making it a Category 3 on the five-step Saffir-Simpson hurricane scale.
a 15- to 20-foot (4.5- to 6-meter) storm surge would spill over local levees in the low-lying region and that rains up to 25 inches were possible.
"This will bring Gulf waters as far north as the Interstate 10 (highway) corridor from Beaumont to Lake Charles," the weather service said.
The refinery town of Port Arthur, Texas, better known as the hometown of late rock singer Janis Joplin, was expected to get severe flooding, officials said.
Rita was the second powerful hurricane to strike the Gulf Coast in less than a month, following, killing at least 1,069 people.
Together, the two storms knocked out nearly all energy production in the offshore oil fields of the Gulf of Mexico and 30 percent of the nation's refining capacity onshore.
Houston, the center of the U.S. oil industry, got gusty winds and intermittent rains but did not take a direct hit from Rita.
"It's too early to say Texas dodged the bullet--Houston did--but we haven't seen what kind of flooding there might be," said Kathy Walt, spokeswoman for Texas Gov. Rick Perry.
News reports said a 200-foot (61 meter) container ship was adrift in Lake Charles, 35 miles north of the Gulf of Mexico, and threatened to strike an Interstate 10 bridge over the lake.
The storm's path reminded many of Hurricane Audrey, which inundated southwestern Louisiana in 1957, killing at least 390 people.
"It's just like Audrey. I was 9 years old and it was terrible," said Phillis Carbalan of Lake Charles.
While officials warned that Rita would strike a catastrophic blow, in Galveston's Poop Deck bar overlooking the Gulf the mood was light as bar-goers drank and watched the roiling surf.
"Mother Nature must be a Yankee lady," said personal chef Samantha Gallion. "It's like she's angry at the southern coast. She's hit us all now."
"I'm joking in the face of disaster."
Most of the storm area was devoid of people after more than 2 million fled the area in a mass evacuation that turned chaotic in Texas.
Traffic jams 100 miles long clogged highways leading out of Houston, stranding thousands of motorists who ran out of gas as they inched along for hours on roads headed inland.
The chaos turned fatal on Friday when a bus carrying residents of a Houston nursing home exploded near Dallas, killing 24 people. Oxygen tanks used by many of the victims exploded in the fire and turned the bus into a charred hulk.
Local officials urged all those who evacuated to take their time coming home to avoid creating a huge inbound traffic jam.
Even though Rita hit 200 miles to the west of New Orleans, the scarred city felt the effects when high tides from the storm spilled over the city's fractured levee system.
In scenes reminiscent of the days after Katrina struck on August 29, water from the city's industrial canal filled up streets in the Ninth Ward and St. Bernard Parish where nearly all the homes are already ruined.