A powerful summer storm slammed into the St. Louis area Wednesday evening, toppling buildings, street lights, tractor trailers and hundreds of trees.

At least 476,000 customers lost power, Metrolink was shut down and just one-third of flights were getting in and out of Lambert Field.

"This is one of the worst storms we can all remember to hit the city of St. Louis in recent years," St. Louis Mayor Francis Slay said at a hurriedly called news conference.

The power outages will present a challenge to utility crews trying to get the power back on in temperatures expected to exceed 100 degrees today.

Until Wednesday, the two biggest storms to hit the area in the last few years were in July 2004, when about 225,000 lost power, and in August 2005, which affected about 250,000. It took AmerenUE crews four days to restore power to all customers in 2004 and five days in 2005.

The storm brewed quickly in central Illinois and swept southwest toward the St. Louis area shortly after 7 p.m. Meteorologists said the storm was unusual, not because of its path, but because a powerful "gust front" preceded the rain and thunder, causing damage from St. Charles County in the west to Madison County in the east, but hitting St. Louis and St. Louis County hardest.

Skies darkened with blowing dust, shingles flew from roofs, and windows were shattered, all before a drop of rain fell. Blowing dust and debris and then torrents of rain limited visibility on roads.

Westbound lanes of Highway 370 were shut down at the Discovery Bridge across the Missouri River because of at least two overturned tractor-trailers, according to the Missouri Highway Patrol. In downtown St. Louis, part of the Switzer building near the Eads Bridge collapsed onto the bridge, trapping a driver - eight months pregnant - in her car for some time.

Near Lambert Field, strong winds ripped off part of the terminal roof and dumped it across several lanes of Interstate 70. Power was out to all but the East Terminal. The airport was open to some flights but with heavy delays.

Drivers heading east on I-70 near the airport could see camper shells strewn across the highway, twisted sheet metal wrapped around light posts and at least one burning building east of the airport.

The eastbound lanes of Interstate 270 near the Chain of Rocks Bridge were closed as emergency crews responded to three tractor-trailers that had flipped over, authorities said.

St. Mary's Health Center in Richmond Heights and Forest Park Hospital in St. Louis were operating on backup power systems Wednesday night.

In St. Louis

Windows in the old Dillards building at 7th Street and Washington Avenue in St. Louis were shattered, covering the streets with a layer of glass. At the Millennium Hotel, a window at Top of the River, the revolving restaurant at the top of the building, was blown out while guests dined.

No one was seriously injured, said Mark Diaz, the hotel's assistant general manager - "just minor, minor cuts."

Winds also shattered a skylight in the south tower, Diaz said. "We are just going to board everything up and get the repair crews out here tomorrow," he said.

At America's Center, bus driver Gaylon Parker, 60, stood huddled at a corner outdoors, watching the storm rip up part of the center's sign.

"This thing was fantastic," he said. "I never saw anything like it my life ... The buses were blowing back and forth."

Parker said he stayed outside during most of the storm to be "adventurous."

"We did finally go inside," he said.

At the Missouri Botanical Garden, hundreds of people who had been attending the Whitaker Music Festival free concert were moved to shelters at the Schoenfeld Auditorium. Damage from shattered glass was reported to the Linnean House, one of the nation's oldest continuously operating greenhouse conservatories. Trees were reported down at the Garden and in neighborhoods around it.

In parts of south St. Louis, trees and limbs almost covered the pavement for whole blocks south of Meramec Street. South of Interstate 55 and in the area around Carondelet Park, motorists had to weave around limbs and thick mats of branches.

Witnesses reported a driver trapped inside a car at Morganford and Arsenal streets. A building collapse at Sidney Street and Lemp Avenue injured two people inside. An empty building near Natural Bridge and Harris avenues also collapsed.

St. Louis officials urged residents to stay within their homes if possible as crews worked to clean up streets. Residents may report downed lines by calling 314-231-1212.

In St. Louis County

In Bellefontaine Neighbors, 100-year-old trees were thrown down, said resident Stephanie Russell, an employee at St. Louis University.

"We had to use four-wheel-drive low just to get up the street," Russell said. "It was everything from water to debris to branches 5 feet to 20 feet long."

Russell said she eventually got to her driveway, but a fallen branch blocked her progress and then another fell behind her car.

"We can't get in or out," she said as neighbors worked to remove branches from the road. "... I've never seen anything like it."

Power went out during the Bridgeton City Council meeting, but the council continued its deliberations. By 8:30, the storm had left the North County area.

In north St. Louis County, the storm caused a gas leak in the 10000 block of Lord Drive. Authorities were evacuating the block, according to St. Louis County police.

Chairmaine Manse and Anna Hollins, customers at the St. Louis Bread Co. at Manchester and Interstate 270 were taken by surprise by the storm.

"It came up as a strong wind, knocking over umbrellas and tables," said Hollins, who lives in Normandy. "It got dark and all hell broke loose . . . I'm willing to go, but I'm not willing to chance it."

In Ladue, Elfriede Olney said at least two oak trees - one about 3 feet in diameter and one more than 50 feet tall - fell in her front yard.

"It's a total disaster area in the front," Olney said. "The driveways are blocked. I've never seen anything like this."

The Dierbergs store in Warson Woods stayed open by generator power and was doing a brisk business in batteries and ice.

In University City, William Conner, was outside late Wednesday night cleaning tree branches and other debris from his driveway. Storms have knocked out power in neighborhood at least a dozen times this year, he said.

"Here we go again," he said. "I hope I don't have to spend another night in the dark."

Kathleen Jensen, a dispatcher for Creve Coeur police, left her home in St. Clair in Franklin County about 8:45 p.m. to drive into St. Louis County to work. Trees were down and lights were out the entire way, but she was especially impressed with the number of road signs that were knocked over.

"We're talkin' the big, huge, green signs that are at the sides of the roads," she said.

In Normandy, neighbors were avoiding downed wires as they worked to clear roads and yards of debris.

The Hazelwood City Council met Wednesday night even though most of the city - including city hall - was without electricity.

"We have a power-point presentation, but no power," Mayor T.R. Carr quipped at one point. Members of the Hazelwood Police Explorer Post who had been meeting at city hall when the storm hit helped get a portable generator working in the council chamber so the meeting could go on.

In other areas

In St. Charles County, tree limbs were down, power was out and the River City Rascals baseball game was canceled.

In Metro East, there were widespread power outages in Fairview Heights. In Glen Carbon, the storm hit quickly about 7 p.m. and moved on without major damage.

In Arnold, Tom and Tana Harris of the 2800 block of Fannie Drive were home with their sons, Levi and Larry, and Larry's girlfriend, Angela Clark, when a tree crashed through the ceiling and the house collapsed. Levi, 5, was trapped.

"The beams fell on him and all I could see were his little feet," his mother said.

Levi was soon rescued and Angela Clark was taken to a hospital with a broken ankle.

In De Soto, the storm caused the collapse of the Spiedel Muffler building.

Shedding some light

At Mike Duffy's Pub & Grill in Kirkwood, manager Marty Smith said the patrons remained calm when the storm hit. But then a concrete street lamp came crashing down onto the driver's side of a red Dodge Caravan parked on West Jefferson.

Smith went from table to table seeking the owner of the car.

"As I approached her, she said, 'I have a red Caravan. Are my lights on?'" Smith recalled. "I said, 'There's a light - on it.'"