The website for Moore, Okla., recommends “that every residence have a storm safe room or an underground cellar.” It says below-ground shelters are the best protection against tornadoes.
But no local ordinance or building code requires such shelters, either in houses, schools or businesses, and only about 10 percent of homes in Moore have them. Plaza Towers Elementary School, where seven children died in Monday’s tornado, lacked an underground shelter.
And the rest of Oklahoma, one of the states in the storm belt called tornado alley, doesn’t require them — despite the annual onslaught of deadly and destructive twisters like the one Monday, which killed at least 24 people, injured hundreds and eliminated entire neighborhoods.
It is a familiar story, as well, in places like Joplin, Mo., and across the Great Plains and in the Deep South, where tornadoes are a seasonal threat but government regulation rankles.
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In 2011, a monster tornado razed large parts of Joplin, killing 160 people in a state that had no storm-shelter requirements. The city considered requiring shelters in rebuilt or new homes but decided that doing so would be “cost prohibitive” because the soil conditions make building basements expensive, the assistant city manager, Sam Anselm, said. Even so, he estimated half the rebuilt homes included underground shelters. Schools were being rebuilt with safe rooms, he said.
In Moore, the website explains that there’s no community shelter because a 15-minute warning is not enough time to get to safety and because, “overall, people face less risk by taking shelter in a reasonably well-constructed residence.”
This is generally true, but not for a storm like Monday’s mile-wide tornado, which was a terrible reminder of a tornado that caused extensive damage on May 3, 1999.
Curtis McCarty, a member of the Oklahoma Uniform Building Code Commission and a builder himself, said the twister Monday would have defeated attempts to resist it above ground. “You cannot build a structure that’s going to take a direct hit from a tornado like that that’s going to stand,” he said.
Residents had about 36 minutes to prepare for the tornado, according to the National Weather Service. The federal agency issued its first warning at 2:40 p.m. local time, 16 minutes before the tornado touched down, said David Andra, a weather-service meteorologist. The tornado reached Moore at 3:16 p.m., he said.
“A 36-minute time period is pretty substantial,” Andra said. The average lead time for tornado warnings is 14 minutes, according to the National Oceanic and Atmospheric Administration.
The city’s website sounds tones that, in retrospect, might seem optimistic. It says the experience in 1999 — “an extremely unique event weather-wise” — meant the standard “shelter in place” methods of protection were adequate. If another storm comes, “there’s only a less than 1 percent chance of it being as strong and violent as what we experienced” before.
Larry Graves, a project manager with Downey Consulting, an engineering company in Oklahoma City that works with schools, said buildings had been upgraded with safe rooms in a piecemeal way in recent years. “You’re seeing more of it, but it’s a big funding item,” he said, noting that a school district might reinforce a large common bathroom with concrete or build an extra-strong gymnasium as a shelter.
Without added protection, Graves said, the drill is the same as it was when he was a schoolboy 40 years ago: “They move you into the hallway, and you stay there tucked up and wait it out.”
Construction in Moore has been studied extensively. In a study published in 2002 in the journal of the American Meteorological Society, Timothy Marshal, an engineer in Dallas, suggested that “the quality of new-home construction generally was no better than homes built prior to the tornado.”
Few homes built after the storm were secured to their foundations with bolted plates, which greatly increase resistance to storms; instead, most were secured with the kinds of nails and pins that had failed in 1999. Just six of 40 new homes had closet-size safe rooms.
Mayor Glen Lewis, of Moore, said that since then the town had strengthened building codes, including a requirement that new homes incorporate hurricane braces. The city has also aggressively promoted the construction of safe rooms and other measures, said Albert Ashwood, the director of the Oklahoma Department of Emergency Management.
Houses in Oklahoma, said McCarty of the building-code commission, are usually built on slabs without basements or crawl spaces because the land is flat and the weather is temperate enough that a deep foundation is not necessary.
Assessment calculations also discourage basement building, he said; assessors value basement square footage at half the rate of ground-level space.
Mike Gilles, a former president of the Oklahoma State Home Builders Association, said that he built safe rooms in all his custom homes.
But asked whether the government should require safe rooms in homes, he said, “Most homebuilders would be against that because we think the market ought to drive what people are putting in the houses, not the government.”
Beyond expense and construction standards, there is a local attitude about tornadoes that borders on temerity. There is a joke among Oklahomans that when the storm sirens sound, instead of taking cover, everyone goes outside and looks for the storm.
Includes material from Bloomberg News