Updated

At least nine children are among two dozen reported dead so far in Moore, the Oklahoma City suburb ravaged by Monday's tornado that packed winds of up to 200 mph.

The twister reduced one elementary school to a heaping mound of rubble and heavily damaged another while also flattening block after block of homes. Officials said early Tuesday the death toll could rise by as many as 40 more as dozens are still unaccounted for.

President Barack Obama has declared a major disaster in Oklahoma as the state begins recovery efforts.  The weather service has tentatively classified the Moore twister's wind speeds as an EF4 on a 5-point scale. Less than 1 percent of all tornadoes reach EF4 or EF5.

Parents and guardians stood in the muddy grass outside a suburban Oklahoma City church, listening as someone with a bullhorn called out the names of children who were being dropped off — survivors of a deadly tornado that barreled through their community.

For many families, the ordeal ended in bear hugs and tears of joy as loved ones reunited. Others were left to wait in the darkness, hoping for good news while fearing the worst.

At St. Andrews United Methodist Church, parents stared into the distance as they waited, some holding the hands of young children who were missing siblings.

Tonya Sharp and Deanna Wallace sat at a table in the church's gymnasium waiting for their teenage daughters. As Sharp and Wallace spoke, a line of students walked in.

Wallace spotted her 16-year-old daughter, who came quickly her way and jumped into her mother's arms, pushing her several steps backward in the process. But Sharp didn't see her daughter, a 17-year-old who has epilepsy. She worried her daughter hadn't taken her medicine.

"I don't know where she's at," Sharp said. Later, she went to speak to officials who helped her register so she could be notified as soon as her daughter was found.

Shelli Smith had to walk miles to find her children. She was reunited with her 14-year-old daughter, Tiauna, around 5 p.m. Monday, but hadn't yet seen her 16-year-old son, TJ, since he left for school that morning.

TJ's phone had died, but he borrowed a classmate's phone to tell his mother where he was. However, Smith couldn't get to him due to the roadblocks. So she parked her car and started walking.

It took her three hours, but a little after sunset, she found him. She grabbed her son and squeezed him in a tight hug that lasted for several seconds before letting go. TJ hugged his sister, and then hugged his mom again.

The family had a long walk back to their car and then home, but she said she didn't mind.

"I was trying to get him and they wouldn't let me," she said, adding later: "I was like, 'You know what? I'm going to get my son.'"

Renee Lee summed up the struggle for many parents with multiple children — find the ones who they hadn't yet seen, while calming the younger ones they had with them.

Lee is the mother of two daughters Sydney Walker, 16, and Hannah Lee, 8. When the storm came, she tried to pick Sydney up from school. Sydney told her on the phone that they wouldn't let her come in. While Lee and her younger daughter waited in their home, which wasn't hit, Sydney was safe in the room at a local high school.

Lee said she believed Sydney wasn't hurt and seemed resigned to the severe weather outbreaks.

"There's been so many of them, it doesn't even faze me," she said. "You just do what you gotta do. It's part of living here."

The biggest known tornado was nearly 2 1/2 miles wide at its peak width, which the weather service describes as near the maximum size for a tornado. It struck Hallam, Neb., in May 2004.

The deadliest tornado, which struck March 18, 1925, killed 695 people in Missouri, Illinois and Indiana.

"It's scary. It's scary. I mean, I have no words to describe it, because it's horrible," an unidentified Oklahoma resident told CNN. "I'm out here looking for my niece, Nancy Rodriguez. Also my sister Sandra Rodriguez is missing. I haven't heard from her, and the situation out here is just devastating. It is very bad."

The devastation -- an eyewitness account

Oklahoma City-based AP photographer Sue Ogrocki was at the elementary school destroyed by a tornado and saw rescuers pulling children out of the rubble. This is her account of what she witnessed.

I left the office as soon as I saw the tornado warnings on TV. I had photographed about a dozen twisters before in the past decade, and knew that if I didn't get in my car before the funnel cloud hit, it would be too late.

By the time I got to Moore, all I could see was destruction. I walked toward a group of people standing by a heaping mound of rubble too big to be a home. A woman told me it was a school.

I expected chaos as I approached the heaping mounds of bricks and twisted metal where Plaza Towers Elementary once stood. Instead, it was calm and orderly as police and firefighters pulled children out one-by-one from underneath a large chunk of a collapsed wall.

Parents and neighborhood volunteers stood in a line and helped pass the rescued children from one set of arms to another to get them out of harm's way. Adults carried the children through a field littered with shredded pieces of wood, cinder block and insulation to a triage center in a parking lot.

They worked quickly and quietly so rescuers could try to hear voices of children trapped beneath the rubble.

Crews lifted one boy from under the wall and were about to pass him along the human chain, but his dad was there. As the boy called out for him, they were reunited.

In the 30 minutes I was outside the destroyed school, I photographed about a dozen children pulled from under the rubble.

Some looked dazed. Some cried. Others seemed terrified.

But they were alive.

I know students are among those who died in the tornado, but for a moment, there was hope in the devastation.

Based on reporting by The Associated Press.

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