Soon after a monstrous, deadly tornado slammed into the community of Moore, Tiffany Thronesberry's phone rang. Her mother was screaming down the line.
"Help! Help! I can't breathe. My house is on top of me," Barbara Jarrell yelled to her daughter.
Ms Thronesberry rushed to her mother's home, where first responders had already pulled her from the rubble.
Around them were scenes of carnage left behind by the enormous tornado, at least 800 metres wide, that roared through Moore and Oklahoma City suburbs, flattening entire neighbourhoods and destroying an elementary school with a direct blow as children and teachers huddled against winds up to 320km/h.
The state medical examiner's office cut the estimated death toll by more than half but warned that the number was likely to climb again. At least 24 people were killed, including at least nine children.
Barbara Jarrell, hospitalised for treatment of cuts and bruises, was one of more than 145 people injured in the devastating twister. Many children were pulled injured from the twisted remains of their school, Plaza Towers Elementary.
The storm laid waste to scores of buildings in Moore, a community of 41,000 people about 16km south of Oklahoma City. Block after block lay in ruins. Homes were crushed into piles of broken wood. Cars and trucks were left crumpled on the roadside. Rescuers launched a desperate rescue effort at the elementary school, pulling children from heaps of debris and carrying them to a triage centre.
"My neighbourhood is gone. It's flattened. Demolished. The street is gone. The next block over, it's in pieces," said Moore resident Kelcy Trowbridge.
"This is terrible. This is war-zone terrible," said a helicopter reporter for a local TV station. "This school is completely gone ... this whole area is destroyed."
The National Weather Service estimated that the tornado reached up to 800m wide and was an EF-4 on the enhanced five-point Fujita scale, the second most powerful type of twister.
Search-and-rescue efforts were continuing throughout the night.
In video of the storm, the dark funnel cloud could be seen advancing slowly across the green landscape. As it churned through the community, the twister scattered shards of wood, awnings and glass all over the streets.
Oklahoma Governor Mary Fallin deployed National Guard members and activated extra highway patrol officers.
She also spoke to President Barack Obama, who declared a major disaster and ordered federal aid to supplement state and local recovery efforts.
"Hearts are broken" for parents looking for their children, Ms Fallin told a news conference.
A Facebook page was set up by a desperate community. "Looking for 5yo Harry," said one message.
At the church where the surviving children were being taken, parents waited, some holding the hands of young children who were missing siblings.
Tonya Sharp and Deanna Wallace sat at a table in a church gymnasium waiting for their teenage daughters. As they spoke, a line of students walked in.
Ms Wallace spotted her 16-year-old daughter, who quickly came her way and jumped into her mother's arms. But Ms 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," she said.
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. Mr Rushing believed he would be safer there.
"About two minutes after I got there, the school started coming apart," he said.
Don Denton hadn't heard from his two sons since the tornado hit the town, but the man who has endured six back surgeries and walks with a severe limp said he walked about 3km as he searched for them.
As reports of the storm came in, Mr Denton's 16-year-old texted him, telling him to call.
"I was trying to call him, and I couldn't get through," Mr Denton said.
Eventually his sons spotted him in the crowd. They were fine, but upset to hear their grandparents' home was destroyed.
As dusk began to fall, heavy equipment was rolled up to the school, and emergency workers crawled among the ruins, searching for survivors.
The tornado also destroyed the city hospital and numerous businesses. Moore Mayor Glenn Lewis watched it pass through from his jewellery shop.
"All of my employees were in the vault," Mr Lewis said.
Mr Lewis, who was also the mayor of Moore when the strongest tornado on record whipped the city in 1999, said the storm won't deter the community from rebuilding.
Chris Calvert saw the tornado from about 1.6km 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."
Oklahoma City police Captain Dexter Nelson said downed power lines and open gas lines posed a risk in the aftermath of the system.
THE 10 DEADLIEST US TORNADOES SINCE 1900:
• 695 deaths. March 18, 1925, in Missouri, Illinois and Indiana.
• 216 deaths. April 5, 1936, in Tupelo, Miss.
• 203 deaths. April 6, 1936, in Gainesville, Ga.
• 181 deaths. April 9, 1947, in Woodward, Okla.
• 158 deaths. May 22, 2011, in Joplin, Mo.
• 143 deaths. April 24, 1908, in Amite, La., and Purvis, Miss.
• 116 deaths. June 8, 1953, in Flint, Mich.
• 114 deaths. May 11, 1953 in Waco, Texas.
• 114 deaths. May 18, 1902 in Goliad, Texas.
• 103 deaths. March 23, 1913, in Omaha, Neb.
OKLAHOMA TORNADO TRACKED PATH OF 1999 TORNADO:
Today's powerful tornado in suburban Oklahoma City loosely followed the path of a killer twister that slammed the region in May 1999.
The National Weather Service estimated that the storm that struck Moore, Oklahoma, today had wind speeds of up to 320 kph, and was up to 1 kilometre wide. The 1999 storm had winds clocked at 480 kph, according to the weather service website, and it destroyed or damaged more than 8,000 homes, killing at least two people.
Kelsey Angle, a weather service meteorologist in Kansas City said it's unusual for two such powerful tornadoes to track roughly the same path. The 1999 twister was part of a two-day outbreak sweeping mostly across central Oklahoma - similar to the past two days.
The weather service has tentatively classified the Moore twister's wind speeds as an EF4 on a 5-point scale. Angle said less than 1 per cent of all tornadoes reach EF4 or EF5.
The thunderstorm developed in an area where warm moist air rose into cooler air. Winds in the area caused the storm to rotate, and that rotation promoted the development of a tornado. The most destructive and deadly tornadoes develop from rotating thunderstorms.
The biggest known tornado was nearly 4 kilometres 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.
Deaths from twisters have been declining in recent years because of improved forecasts and increased awareness by people living in tornado-prone areas, especially in smaller and rural communities.
TORNADOES IN NEW ZEALAND:
About 20 to 30 tornadoes happen in New Zealand each year, most frequently in the west and north. Tornadoes sometimes occur during thunderstorms, are sometimes preceded by a long, continuous roar or rumble, and generally last less than 15 minutes.
Damage paths are 10 to 20 metres wide and are usually less than five kilometres long.
WHAT TO DO:
• Develop a household emergency plan and prepare a portable getaway kit.
• When a warning is issued, alert others if possible.
• Take shelter in a basement or interior room without windows on the lowest floor, and get under sturdy furniture.
• Close windows, external and internal doors.
• Don't walk around outside, and avoid driving unless absolutely necessary.
• After the storm, listen to local radio stations for updates and advice from emergency management officials.
• Ask your council for advice on how to clean up debris safely.
Source: Ministry of Civil Defence and Emergency Management
- AP, AFP, AAP and APNZ