MOORE, OK (CBSDFW.COM/AP) – A massive tornado plowed through central Oklahoma Monday, flattening homes, schools and businesses and killing at least 24 people, including seven children.

The state medical examiner’s office previously reported that 51 people had died, but the number was officially lowered on Tuesday morning. Spokeswoman Amy Elliot said Tuesday morning that she believes some victims were counted twice in the early chaos of the storm.

In the 30 minutes it was on the ground, it flattened entire neighborhoods and destroyed an elementary school with a direct blow as children and teachers huddled against winds up to 200 mph.

The storm laid waste to scores of buildings in Moore, a community of 41,000 people about 10 miles south of the city. The aftermath looked like an enormous broom swept over the neighborhood. Homes were splintered into piles of broken wood. Cars and trucks were left crumpled on the roadside like used candy wrappers. Block after block lay in ruins.

Reports of casualties started coming in shortly after the twister hit. Hospital officials remained on emergency alert during the day as victims with all types injuries were brought in.

More than 140 people were being treated at hospitals, including about 70 children. And search-and-rescue efforts were to continue throughout the night.

One hospital in Moore was hit by the tornado, and patients were evacuated.

Moore resident Tiffany Thronesberry said she heard from her mother, Barbara Jarrell, shortly after the tornado.

“I got a phone call from her screaming, ‘Help! Help! I can’t breathe. My house is on top of me!'” Thronesberry said.

Thronesberry hurried to her mother’s house, where first responders had already pulled her out. Her mother was hospitalized for treatment of cuts and bruises.

According to CBS 11 Meteorologist Larry Mowry, radar signatures indicated the storm was as large as two miles wide at one point.

The National Weather Service issued an initial finding that the tornado was an EF-4 on the enhanced Fujita scale, the second most-powerful type of twister.

The powerful tornado first touched down in Newcastle and churned toward Interstate 44 and S.W. 149th Street. It hit Plaza Towers Elementary School, which is northeast of S.W. 19th and Santa Fe.

Parents were seen running to the school. Rescuers launched a desperate rescue effort at the school, pulling children from heaps of debris and carrying them to a triage center.

Oklahoma Gov. Mary Fallin deployed 80 National Guard members to assist with rescue operations and activated extra highway patrol officers.

Fallin also spoke with President Barack Obama, who offered the nation’s help and gave Fallin a direct line to his office.

Many land lines to stricken areas were down, and cellphone networks were congested. The storm was so massive that it will take time to establish communications between rescuers and state officials, the governor said.

In video of the storm, the dark funnel cloud could be seen wreaking havoc slowly across the green landscape. As it churned through the community, the twister scattered shards of wood, awnings and glass all over the streets.

Chris Calvert saw the menacing tornado from about a mile away.

“I was close enough to hear it,” he said. “It was just a low roar, and you could see the debris, like pieces of shingles and insulation and stuff like that, rotating around it.”

Even though his subdivision is a mile from the tornado’s path, it was still covered with debris. He found a picture of a small girl on Santa Claus’ lap in his yard.

Volunteers and first responders raced to search the debris for survivors.

At Plaza Towers Elementary School, the storm tore off the roof, knocked down walls and turned the playground into a mass of twisted plastic and metal.

Children from the school were among the dead, but several students were pulled alive from the rubble. Rescue workers passed the survivors down a human chain to the triage center in the parking lot.

James Rushing, who lives across the street from the school, heard reports of the approaching twister and ran to the school, where his 5-year-old foster son, Aiden, attends classes. Rushing believed he would be safer there.

“About two minutes after I got there, the school started coming apart,” he said.

The students were sent into the restroom.

As dusk began to fall, heavy equipment was rolled up to the school, and emergency workers wearing yellow crawled among the ruins, searching for survivors.

Because the ground was muddy, bulldozers and front-end loaders were getting stuck. Crews used jackhammers and sledgehammers to tear away concrete, and chunks were being thrown to the side as the workers dug.

Douglas Sherman drove two blocks from his home to help.

“Just having those kids trapped in that school, that really turns the table on a lot of things,” he said.

A map provided by the National Weather Service showed that the storm began west of Newcastle and crossed the Canadian River into Oklahoma City’s rural far southwestern side about 3 p.m. When it reached Moore, the twister cut a path through the center of town before lifting back into the sky at Lake Stanley Draper.

Oklahoma City Police Capt. Dexter Nelson said downed power lines and open gas lines posed a risk in the aftermath of the system.

Monday’s powerful tornado loosely followed the path of a killer twister that slammed the region in May 1999.

The weather service estimated that Monday’s tornado was at least a half-mile wide. The 1999 storm had winds clocked at 300 mph.

Kelsey Angle, a weather service meteorologist in Kansas City, Mo., said it’s unusual for two such powerful tornadoes to track roughly the same path.

It was the fourth tornado to hit Moore since 1998. A twister also struck in 2003.

Monday’s devastation in Oklahoma came almost exactly two years after an enormous twister ripped through the city of Joplin, Mo., killing 158 people and injuring hundreds more.

That May 22, 2011, tornado was the deadliest in the United States since modern tornado record keeping began in 1950, according to the National Oceanic and Atmospheric Administration. Before Joplin, the deadliest modern tornado was June 1953 in Flint, Mich., when 116 people died.

Click here for a list of several shelters in Moore for those affected by the tornado.

Television coverage from the area showed wide spread destruction. Several homes appeared to be completely destroyed and debris was strewn about the affected community.

Click Here the Latest Information From CBS News 9 in Oklahoma City.

This twister was the latest in a group of violent storms that swept through the Midwest, starting Sunday, that has now left dozens of people dead.

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