MOORE, Oklahoma -- Rescuers dug through the debris of destroyed homes, schools and businesses Tuesday in a desperate search for survivors of the massive tornado that blasted through this Tornado Alley town, killing at least 24 people and injuring more than 200.
The National Weather Service said it determined the twister was the strongest type, EF-5, packing incredible fury with winds of more than 200 mph. A day earlier it had said the storm was an EF-4.
Efforts were hindered by Tuesday's unsettled weather, which included bouts of hail and lightning. Additionally, roads were clogged by debris and the thousands of residents trying to return home and check their damage.
Gary Bird, Moore fire chief, said searchers hope to thoroughly examine every structure and vehicle by Tuesday night.
Also Tuesday, authorities dramatically reduced the number of confirmed dead after earlier reporting that at least 51 people had died in Monday's storm.
Amy Elliot, spokeswoman for the state medical examiner's office, blamed the confusion on chaos after the storm cut a path more than a mile wide through this Oklahoma City suburb of 41,000 people. She said nine of the dead were children, and that the death toll could climb.
"We will rebuild, and we will regain our strength," Gov. Mary Fallin said at an afternoon press conference.
Fallin said at least 237 people were injured and that officials are working to develop "firm" casualty numbers. Fallin also praised the Federal Emergency Management Agency and its administrator, Craig Fugate -- and thanked first responders for a "job well done."
The National Weather Service spokeswoman Keli Pirtle said Tuesday the agency upgraded the tornado from an EF-4 on the enhanced Fujita scale to an EF-5 based on what a damage assessment team saw on the ground. The weather service uses the word "incredible" to describe the power of EF-5 storms.
The weather service says the tornado's path was 17 miles long and 1.3 miles wide.
Pirtle says Monday's twister is the first EF-5 tornado of 2013.
On average, over 1,000 tornadoes hit the U.S. each year, and only one might be an EF-5, reports National Climatic Data Center. Since the early 1950s, only 59 EF-5 tornadoes have hit the USA, according to the Tornado History Project. Moore, Okla., has been hit by two of those.
Everyone was a first responder in Moore. When the storm destroyed the Plaza Towers Elementary School, rescue workers passed the survivors down a human chain of parents and neighborhood volunteers. Parents carried children in their arms to a triage center in the parking lot.
Firefighter Russ Locke was among those who helped search through the school's crushed remains, where about 75 students and staff had huddled when the tornado hit. Several children were killed there; others were pulled alive from the wreckage.
"You have your own kids, and you want to find other people's kids and for it all to be OK," Locke said, tearing up. "And sometimes it doesn't work out like that."
About a mile away, the walls tumbled down at Briarwood Elementary. Miraculously, no one there died.
The tornado stormed east across town, snapping 30-foot trees in half, crushing homes and hurling chunks of aluminum siding like missiles.
Jalayne Jann, 40, had just arrived home from work when the tornado descended on her neighborhood. She grabbed two of her five dogs and dashed into her underground concrete shelter, emerging minutes later to an apocalyptic scene: two walls to her brick home pulverized, trees down, cars crushed and homes for miles in either direction flattened.
"Shocked," she said Tuesday as she surveyed her ruined home. "We've lived here a long time. We're used to tornadoes. But they always go around or over. Nothing ever like this."
Johnnie Schatswell, 70, piled his wife, Vivian, and two dogs into a bathtub and laid atop them as the tornado crushed his home. Boards and bricks pelted his back as the storm intensified. Later, a neighbor yanked back a collapsed kitchen wall to help free them, he said.
"It's like a roar I've never heard before," he said of the storm. "And never want to hear again."
Even in areas where destruction was not complete, pieces of fencing were scattered across once-green lawns now covered in mud and chunks of wood. Garage doors were buckled and ripped from hinges, cars had been smashed by flying debris.
Judy Odom, who has lived in the same home here for 40 years, said she stayed there Monday night despite some damage.
"I don't even know what I'm supposed to do," she said. "I suppose I'll go talk to my insurance company."
FULL COVERAGE: Twisters devastate Okla. City suburbs
Trisha Ulrey, 46, said she had just pulled into the parking lot of Highland West Junior High to pick up her children, Rachel, 14, and Jacob, 12, when she was told the storm was too close -- school officials weren't letting students go.
"People were screaming mad," Ulrey said. "They wanted to go home to their own shelters. But teachers were saying, 'You can die between here and your shelter.'"
The storm roared around them and the school's roof rattled. After the 45-minute ordeal was over, she said she knew school officials had done the right thing.
"It could have been much, much worse if they had let them go," Ulrey said.
President Obama, who declared a major disaster in Oklahoma late Monday, spoke to the nation Tuesday morning. The president, who had just received a briefing on recovery efforts, said Oklahoma "will have all the resources they need at their disposal."
Pope Francis tweeted: "I am close to the families of all who died in the Oklahoma tornado, especially those who lost young children. Join me in praying for them."
The were concerns that the area might be victimized by charity scams. Oklahoma Attorney General Scott Pruitt dispatched more than 30 investigators Tuesday to conduct investigations.
"The first scam we typically see after devastation like this is charity fraud," Pruitt said. "For those folks around the country who want to donate funds to help families in Oklahoma, please be alert and only donate to reputable relief charities such as the Salvation Army or the Red Cross."
The Red Cross said it was accepting $10 pledges from people who text "REDCROSS" to 90999. People can also donate at the organization's website.
Claudia Todd, immediate past president of the district PTA in Moore, said the action officials at Plaza Towers Elementary took Monday afternoon as a monstrous tornado took aim at them is a routine drill practiced monthly at most schools in the district.
Along with fire drills, sheltering in place for extreme storm events are practiced at least once a month, where students and teachers practice filing into interior classrooms during storms, she said. When a freshman joins a school, they also take home a procedure book with items such as dress code - and the carefully explained shelter drill.
"You take those precautions seriously, especially in Oklahoma," said Todd, who also works as a junior attendance secretary at nearby Southmoore High School.
After the May 1999 tornado, those drills were practiced with even more seriousness, she said.
"When you hear those warnings, you don't just go, 'It's just another warning,'" Todd said. "You take them seriously."
The National Weather Service said Monday that the tornado spent 40 minutes on the ground, a 20-mile swath of death with winds approaching 200 mph.
Moore is no stranger to such tragedy; the Tornado Alley town was torn apart by another massive twister 14 years ago.
On May 3, 1999, a record-setting EF-5 tornado obliterated the city of 55,000 with winds measured at 318 mph, the highest ever on the earth's surface. The storm killed 36 people, injured hundreds and caused about $1 billion in damage.
The National Weather Service in Norman, Okla., said a tornado warning was in effect Monday afternoon for 16 minutes before the twister developed. The tornado was given a preliminary rating of EF-4.
VIDEO: Time lapse of tornado
"We've been through this before,'' City Manager Steve Eddy said, referring to the 1999 tornado and others over the years. "Our citizens are resilient.
On Sunday, a tornado packing winds as high as 200 mph left two people dead in Oklahoma. Tornadoes and high winds injured more than 20 in the region.
Steve Bowen, of global reinsurance firm Aon Benfield, estimated that the Moore tornado could become only the fourth in world history to cause non-inflation adjusted economic losses "beyond $1 billion."
So far this year - not including this most recent five-day outbreak - severe storms have caused $3.5 billion in economic losses in the USA, Bowen said. Of that $3.5 billion, at least $2 billion was covered by insurance.
"By the time the current storm system finally winds down by the middle of this week, I wouldn't be surprised if this ends up as the costliest U.S. natural disaster event we've seen so far in 2013," said Bowen.
Trevor Hughes reports for The Coloradoan in Fort Collins; Jonathan Shorman for The News-Leader in Springfield, Mo.
Contributing: Doyle Rice; Donna Leinwand Leger, Laura Petrecca, William M. Welch, USA TODAY; The Associated Press
Trevor Hughes, Rick Jervis, Jonathan Shorman and John Bacon, USA TODAY