MOORE, Okla. -- The tornado that tore through an Oklahoma City suburb destroyed or damaged as many as 13,000 homes and may have caused $2 billion in overall damage, officials said Wednesday.
State authorities meanwhile said two infants were among the 24 people who perished in the twister.
Oklahoma Insurance Department spokeswoman Calley Herth told The Associated Press that the early damage tally is based on visual assessments of the extensive disaster zone that stretches more than 27 kilometres and the fact that Monday's tornado was on the ground for 40 minutes.
The financial cost of the tornado in Moore could be greater than the $2 billion in damage from a 2011 tornado that killed 158 people in Joplin, Missouri, Herth said, adding that the Joplin twister left a smaller trail of destruction.
For the first time Wednesday, authorities provided a clearer accounting of the destruction in Moore, a town of about 56,000 in a central U.S. region known as Tornado Alley. Moore was also hit by a massive tornado in 1999.
Between 12,000 and 13,000 homes were destroyed or damaged and 33,000 people were affected in some way by the storm, said Oklahoma City Mayor Mick Cornett, speaking at a news conference. He also put the monetary damage estimate at between $1.5 billion to $2 billion.
Emergency officials were unable to put a figure on the number of people left homeless, because many people have been taken in by relatives and only a few dozen have stayed overnight at Red Cross shelters.
Six adults remain unaccounted for since the tornado, said Oklahoma Department of Emergency Management Director Albert Ashwood. It's possible those people had just "walked off" their properties or could still be found in the rubble, Ashwood said.
President Barack Obama will travel to Moore on Sunday to view the damage first-hand and meet with victims and emergency personnel. Secretary of Homeland Security Janet Napolitano visited the area Wednesday, pledging the government's support.
Dan Ramsey, president of the Independent Insurance Agents of Oklahoma, said a damage estimate in the low billions is "not surprising."
"Certainly it's in the hundreds of millions," Ramsey said. "I suppose seeing projections from similar disasters, it could stretch to a billion" or more.
The National Weather Service said the tornado was a top-of-the-scale EF5 twister with winds of at least 320 kph -- the first EF5 tornado of 2013.
The Oklahoma medical examiner's office announced that it has positively identified 23 of the 24 people who died in the tornado, and that 10 of those killed are children.
All of the children have been identified, among them a 4-month-old and a 7-month-old. Both babies died from head injuries. The eight other children ranged in age from 4 years to 9 years. Of those, six were suffocated. The other two died from massive injuries.
Mayor Glen Lewis said Wednesday he would propose an ordinance in the next couple of days to modify building codes to require that every new home in the town would have a reinforced tornado shelter.
Underground safe rooms are typically built below garages and can cost around $4,000.
Residents clearing massive piles of debris were also trying to get hold of essentials like mobile phones and prescription drugs lost in the destruction. Cellular service providers set up mobile retail outlets and charging stations. At least one was offering free phone calls and loaner phones.
Insurance companies have also set up emergency operation centres to take calls from people trying to get prescriptions filled and handle other health care needs.
The emotional trauma of the destruction compounded the tornado's cost.
With her son holding her elbow, 83-year-old Colleen Arvin walked up her driveway Tuesday to see what was left of her home of 40 years.
Part of the roof was sitting in the front yard, and the siding from the front of her home for the past 40 years was gone. As her son and grandsons picked through what was left of her belongings, Arvin found some dark humour in the situation.
"Oh thank God," she said, laughing, when a grandson brought over her keys. "We can get in the house."
