MOORE, Oklahoma (CNN) -- [Breaking news update at 3:59 p.m.]
Damage assessments show that the tornado that struck central Oklahoma on Monday was an EF5 -- meaning it had winds of 200 mph or greater -- for at least some of the time it was ravaging an area near Oklahoma City, the National Weather Service says. The weather service said its crews found at least one area with damage indicative of an EF5 tornado.
[Original story posted at 3:26 p.m.]
Oklahoma tornado spread destruction like a 'two-mile-wide lawnmower blade'
Amid downed power lines, hissing gas pipes and immense devastation, rescuers searched "board by board" Tuesday for survivors and victims of a massive tornado that pulverized a vast swath of the Oklahoma City suburbs.
It was a daunting task. The Monday afternoon storm carved a trail through the area as much as two miles wide and 17 miles long, officials said. Hardest hit was Moore, Oklahoma -- a suburban town of about 56,000 and the site of eerily similar twisters in 1999 and again four years later.
At a Tuesday afternoon news conference, Oklahoma Gov. Mary Fallin said the storm was one of the "most horrific storms and disasters that this state has ever faced."
All that remained in some places, she said, were "sticks and bricks."
The state medical examiner's office said 24 people were confirmed dead, including nine children.
Earlier reports of at least 51 deaths were erroneous, said Amy Elliot, chief administrative officer for the Oklahoma Office of the Chief Medical Examiner.
But Fallin said the death toll could still rise. She said some bodies may have been taken to funeral homes without the government's knowledge.
More than 230 people were injured.
At least 100 people have been pulled alive from the rubble by rescuers.
Terri Watkins, the Oklahoma Department of Emergency Management spokeswoman who described Tuesday's search as "board by board," said it was far too soon to account for the devastation of the storm.
"This is a massive tornado and it's a large area that has been struck," she said.
The scene -- block after block of flattened homes and businesses, the gutted remains of a hospital and hits on two elementary schools -- left even seasoned veterans of Oklahoma's infamous tornadoes reeling.
The devastation was so complete, Moore Mayor Glenn Lewis said city officials were racing to print new street signs to help guide rescuers and residents through a suddenly twisted and unfamiliar landscape.
Lt. Gov. Todd Lamb likened the destruction to a "two-mile-wide lawnmower blade going over a community."
Police, firefighters, volunteers and nearly 180 National Guard troops joined forces Tuesday in searching the rubble and securing areas hit by the storm. Texas sent an elite 80-member urban search team as well, and the American Red Cross sent 25 emergency response vehicles.
The weather wasn't cooperating with their efforts: National Weather Service crews surveying the damage in Moore reported rain, half-inch hail and 45-mph winds over the debris field.
The Oklahoma Highway Patrol asked motorists to steer clear of Interstate 35 near Moore to free up lanes for disaster response resources streaming into the area.
And so many people were showing up to volunteer that authorities had to plead with would-be rescuers to stay away.
Path of devastation
The storm struck near Newcastle, Oklahoma, at 2:56 p.m. Monday -- 16 minutes after the first warnings went out, according to the National Weather Service.
Moore residents had another 30 to 40 minutes before the massive storm entered the western part of the city, CNN meteorologist Sean Morris said.
As Fallin had said Monday night, Lamb said he believed residents had time to prepare for the storm.
"My understanding is that the warning system was good. It was adequate," he said.
Among the many buildings struck by the storm were two schools: Plaza Towers and Briarwood elementaries.
About 75 students and staff members were hunkered down in Plaza Towers when the tornado struck, CNN affiliate KFOR reported.
At one point, an estimated 24 children were missing from the school, but some later turned up at nearby churches.
On Monday, a father of a third-grader still missing sat quietly on a stool outside. Tears cascaded from his face as he waited for any news.
Even parents of survivors couldn't wrap their minds around the tragedy.
"I'm speechless. How did this happen? Why did this happen?" Norma Bautista asked. "How do we explain this to the kids? ... In an instant, everything's gone."
Across town, Moore Medical Center took a direct hit.
"Our hospital has been devastated," said Lewis, the Moore mayor. "We had a two-story hospital, now we have a one. And it's not occupiable."
So 145 of the injured were rushed to three other area hospitals.
That number includes 45 children taken to the children's hospital at Oklahoma University Medical Center, Dr. Roxie Albrecht said. Injuries ranged from minor to severe, including impalement and crushing injuries.
'Cars crumpled up like little toys'
The National Weather Service pegged the tornado's winds at about 190 mph, placing it at the upper end of the EF4 category, the second-most powerful category of storm.
But Rick Smith, a meteorologist for the weather service, told reporters Tuesday that number could go higher.
Weather service assessment crews were just making their way into the most heavily devastated areas Tuesday afternoon, he said.
"We've seen numerous structures that are wiped clean to the foundation." Smith said.
State Highway Patrol Trooper Betsy Randolph told CNN affiliate KOKI that it was "mass devastation."
"I'm talking everywhere you looked, the debris field was so high, and so far and so wide, wounded people walking around the streets," she said. "They were bloody; there were people that had stuff sticking out of them from things that were flying around in the air. There were cars crumpled up like little toys and thrown on top of buildings. Buildings that were two and three stories tall that were leveled."
Storm chaser Lauren Hill was part of a team that recorded video of the massive tornado as it ripped through town.
"You could actually feel the vibration from the tornado itself as it was approaching," she said.
"We still have a bit of PTSD," she said. "It's devastating."
After the ear-shattering howl subsided, survivors along the miles of destruction emerged from shelters to see an apocalyptic vision. Homes and other buildings were shredded to pieces. Remnants of mangled cars were piled on top of each other. What used to be a parking lot now looked like a junkyard.
"People are wandering around like zombies," KFOR reporter Scott Hines said. "It's like they're not realizing how to process what had just happened."
James Dickens is not a firefighter or medic. He's actually a gas-and-oil pipeline worker. But that didn't stop him from grabbing a hard hat and joining other rescuers at Plaza Towers Elementary School.
"I felt it was my duty to come help," he said Tuesday after a long night of searching.
"As a father, it's humbling. It's heartbreaking to know that we've still got kids over there that's possibly alive, but we don't know."
Hiding in freezers
Hines said rescuers found a 7-month-old baby and its mother hiding in a giant freezer. But they didn't survive.
At the devastated hospital in Moore, some doctors had to jump into a freezer to survive, Lamb said.
Lando Hite, shirtless and spattered in mud, described how the storm pummeled the Orr Family Farm in Moore, which had about 80 horses before the storm hit.
"It was just like the movie 'Twister,' " Hite told KFOR. "There were horses and stuff flying around everywhere."
Moore, and the Oklahoma City region, are far too familiar with disaster. In 1995, 168 people died in the bombing of the Alfred P. Murrah Federal Building in Oklahoma City.
In 1999 and then again in 2003, Moore took direct hits from tornadoes that took eerily similar paths to Monday's storm. The 1999 storm packed the strongest wind speeds in history, Lamb said.
"We're a tough state. This is a tough community," Lamb said. "There is hope. We always have hope. We always have faith."
President Barack Obama, pledging whatever federal aid Oklahoma would need, praised teachers who protected their students.
"If there is hope to hold on to -- not just in Oklahoma but around the country -- it's the knowledge that the good people there and in Oklahoma are better prepared for this type of storm than most," he said. "And what they can be certain of is that Americans from every corner of this country will be right there with them, opening our homes, our hearts, to those in need, because we're a nation that stands with our fellow citizens as long as it takes."
More trouble brewing
The storm system that spawned Monday's tornado and several other twisters Sunday isn't over yet.
Southwest Arkansas and northeast Texas, including Dallas, are under the gun for severe weather Tuesday. Those areas could see large hail, damaging winds and tornadoes.
A broader swath of the United States, from Texas to Indiana and up to Michigan, could see severe thunderstorms.
"We could have a round 3," CNN meteorologist Ivan Cabrera said. "Hopefully, it won't be as bad."
CNN's Michael Pearson and Holly Yan wrote and reported from Atlanta, and Gary Tuchman reported from Moore. CNN's George Howell, Dana Ford, Nick Valencia, AnneClaire Stapleton, Phil Gast, Ed Payne, Joe Sutton and Miriam Falco contributed to this report.