REUTERS - The people of central Oklahoma know all too well the destructive power of a tornado, but when a big one rolled toward the town of Moore again on Monday, residents had few basements and storm shelters to run to when the alarm sounded, officials said.
Two elementary schools that were hit by the EF-5 tornado - the most powerful category - did not have "safe rooms" where students could shelter from the storm, and no applications for safe rooms had been made, Oklahoma Emergency Management Director Albert Ashwood told reporters.
Seven of the nine children who died in Monday's tornado perished in the Plaza Towers Elementary School, which took a direct hit.
And while the popularity of above- or below-ground shelters or reinforced "safe rooms" in private homes has grown since a deadly 1999 Oklahoma City area tornado, Oklahoma County has just 6,489 such shelters out of approximately 260,000 residential properties, according to the county's chief deputy assessor, Larry Stein.
Moore, a suburb of 55,000 where most of the 24 deaths tallied so far occurred, was also hard hit by the 1999 tornado.
The reasons for the lack of below-ground shelter range from the financial to the cultural to the geographical. Basements, for example, a staple of homes in much of America, are rarely built in the region. But federal and state programs have aimed to reduce the shelter gap in recent years.
Shelters are "highly recommended" for storm-prone areas, according to Larry Tanner, research associate for the National Wind Institute at Texas Tech University who studies how shelters behave in fierce storms. He believes public buildings should have shelters or safe rooms in areas prone to large storms.
"Schools should all be built with shelters," said Tanner, adding, "I would prefer my taxpayer money being directed toward shelters rather than AstroTurf on ball fields."
In the southern United States, 18.6 percent of occupied homes have at least partial basements, according to 2011 U.S. Census data. By comparison, 84.2 percent of occupied homes in the Northeast and 76.5 percent in the Midwest have full or partial basements.
In the Oklahoma City metropolitan area, 3.5 percent of occupied homes have at least a partial basement, according to the latest available Census data from 2004. Stein said basements are more common in homes built before the 1940s.
"People around here really don't know how to build basements, to be honest," said David Tinsley, assessor for Cleveland County, which includes Moore. He noted that the ground has a lot of clay, and can shift.
Basements are more common in northern U.S. states because of the depth of the frost line, which can affect the stability of a house, Tanner said. But in southern states, the frost line is shallow. "It's cheaper and easier to just build a foundation than to build a basement," he said.
Basements are also uncommon in Joplin, Missouri, which has wet, rocky soil. A 2011 tornado in Joplin killed 161 people.
Basements are no guarantee of safety, since a house can collapse and trap or injure occupants. How the basement is constructed makes a difference, Tanner noted.
A basement does provide a measure of security, because some people killed by storms are swept from their homes, he said.
An alternative to a basement is a safe room, which can be made with reinforced concrete, or an underground or above-ground shelter, Tanner said. There are also plywood and steel designs for safe rooms. A safe room can also be put in a basement.
Most rebuilt homes in Joplin have safe rooms or small underground shelters, according to Joplin City Manager Mark Rohr. They are also being put in new schools and some businesses, he said.
One kind of below-ground storm shelter popular in the Oklahoma City area is in the garage, with a rolling steel door over a small space, according to Stein. These types of shelters can cost $2,500 to $5,000. Some people put their below-ground shelter in the yard. An above-ground safe room can cost anywhere from $4,000 to $12,000, Tanner said.
Tanner said shelters have grown more popular in the wake of damaging tornadoes. Numerous states, including Texas, Oklahoma and Alabama, have shelter-incentive programs, with the federal government providing some matching funds for homeowners. "That has really helped the growth," said Tanner.
With the help of the Federal Emergency Management Agency (FEMA), Oklahoma has funded over 100 school safe rooms, said Ashwood. In addition, many individuals had applied for funds to help build safe rooms in their homes, he said.
FEMA spokesman Dan Watson said that since 1993, FEMA has invested more than $57 million in 11,768 private and public safe rooms in Oklahoma, more structures than in any other state. Many were in the same area as Monday's tornado, he said.
Ali Shahan, 26, said she sheltered during Monday's tornado with her husband and child in a safe room at their church, where her husband is associate pastor. She said she would "love" to have their own shelter but it's too expensive.
"We do not have $2,000 to spend on one," Shahan said.
Rhonda Ramos, 44, of Moore, a daycare provider, sheltered through the storm in a closet with a toddler and a fox terrier. She had tried to get a safe room using FEMA funding but wasn't successful. "This time I'm hoping they'll give more out," she said.
Asked if the children at Plaza Towers would have survived if they were in a safe room, Ashwood said, "not necessarily."
"There's no guarantee that everyone will totally be safe," Ashwood said. "Most of the time, 95 percent of the time ... taking proper tornado procedures and precautions within your own home, you'll survive most tornadoes," Ashwood said. "This was a very unique tornado." (Reporting by Mary Wisniewski, David Bailey, Alice Mannette, Brendan O'Brien, Deborah Charles and Kevin Murphy; Editing by Mary Milliken and Philip Barbara)