Extreme Tornado Outbreaks Are on the Rise, Study Says

Extreme Tornado Outbreaks Are on the Rise, Study Says

The average number tornado outbreaks that bring multiple twisters from a single weather event is on the rise in the U.S., according to new research, and the findings could change the way insurers and disaster preparedness officials respond to tornadoes.

The time to get a Storm Shelter is NOW!

Scientists say the reason isn’t clear but climate change could play a role

The average number tornado outbreaks that bring multiple twisters from a single weather event is on the rise in the U.S., according to new research, and the findings could change the way insurers and disaster preparedness officials respond to tornadoes.

The study, published in the journal Nature Communications, also shows an increased variability in the number of tornadoes from one outbreak to another. Higher variability means that large outbreaks that result in multiple tornadoes can be more common while the total number of tornadoes in a given year remains relatively constant. Tornado outbreaks result in dozens and sometimes hundreds of tornadoes each year and cause billions of dollars in damage. One such outbreak in 2011 resulted in 363 tornadoes in North America that killed more than 350 people.

“It means that when it rains, it really, really, really pours,” says study co-author Joel Cohen, a professor at Rockefeller and Columbia University, in a press release.

The reason behind the change in tornado patterns remains unclear. The short length, unpredictable arrival and relatively small size of tornadoes make them difficult to study. But researchers suggest that climate change may be a possible explanation for the change in patterns. The weather phenomenon occurs during periods of atmospheric instability and when there are large differences in wind speed in a given area known as “wind shear,” both of which could be affected by temperature increases.

“The science is still open,” says study co-author Michael Tippett, a climate and weather researcher at Columbia University, in a press release. “It could be global warming, but our usual tools, the observational record and computer models, are not up to the task of answering this question yet.”

No Basement, No Problem…with an Above Ground Storm Shelter!

Basements scarce in Moore, Oklahoma – CNN.com

 

No Basement, No Problem…with an Above Ground Storm Shelter!

It’s one of the most familiar pieces of advice from authorities to people in the path of a tornado: Get into your basement. Yet few homes in the Oklahoma City area have them — even though that state is hit by far more powerful tornadoes than most others.

“Probably less than one tenth of one percent” of the houses in Moore are built with basements, said Mike Hancock, president of Basement Contractors in Edmond, Oklahoma. “There’s just such a misconception that you cannot do it.”

Why?

Hancock cited the area’s high groundwater levels and heavy clay as among the reasons some people believe — wrongly, he said — that basements are tough to construct.

But improved waterproofing methods can obviate the first; and the second, too, is surmountable, according to Hancock, who said he has built more than 600 basements in the Oklahoma City area over the past 15 years.

 Tornado shelters save lives! 

“We do ’em all day long,” he said. “I’ve got 32 basements to put in the ground right now.”

The city of Moore was the epicenter of an EF5 tornado Monday that decimated neighborhoods in the Oklahoma City area, leaving at least 24 dead.

Inside a tornado-ravaged school

In Moore, other issues can dissuade new home buyers from investing in basements, Hancock said. One is that there are so few other such houses that comparable values are tough to estimate, “so appraisers don’t give you any credit.”

In fact, basements are so rare in the area that real estate listings do not include “basement” as an option under foundation types, he said.

“You can list it in the comments section, but that’s not a foundation type.” That means it’s hard for house hunters to narrow their searches to houses with basements, which makes it harder still for sellers who have built houses with basements to recoup their investments, he said.

Moore in bull’s-eye twice, science may know why

Mike Barnett, a custom homebuilder in the area for 37 years, estimated that some 2% of residents have basements, and 10% to 15% “have some kind of cellar.”

None of the homes in his partially completed, 51-house development, called Autumn Oaks, has a basement, he said. Though it was spared Monday’s storms, “a block north of us it looks like Bosnia,” he said. He plans to build a community shelter that would accommodate all of its residents.

Alternatives exist: An above-ground shelter runs $8,000 to $10,000; a small basement would cost $15,000 to $20,000; and a concrete cellar built during new-house construction would cost as little as $2,200, said Barnett.

Tornado prediction is improving, scientists say

Accessibility an important element

Basements provide good protection if equipped with a suitable door and a concrete roof, but basements of pier-beam houses would leave their occupants exposed and vulnerable if the structure above them were blown away, said Ernst Kiesling, a former professor of civil engineering at Texas Tech.

Kiesling created the concept of the above-ground storm shelter after a tornado swept through Lubbock, Texas, in 1970, killing 26 people and demolishing scores of homes.

EF5 tornadoes are terrifying perfect storms

In addition, it is difficult to make basements compliant with the Americans with Disabilities Act, said Kiesling, who is on the research faculty at the school’s National Wind Institute.

Above-ground storm shelters are easy to make accessible to those who are physically challenged, “and I would say that accessibility is a very important element,” Kiesling said.

Specially reinforced safe rooms provide “near absolute occupant protection from even the worst-case tornado,” he said.

How can we be safe from tornadoes?

Other products include steel, concrete and plastic shelters; above-ground and below-ground shelters; indoor and outdoor shelters; and shelters that fit underneath the garage slab.

The extra cost of incorporating a basement into plans for a house depends on where it is being built. “If you’re in the colder climates, then one has to put the foundation walls several feet deep to get below the frost line,” Kiesling said.

A region’s frost line marks where the ground no longer freezes and is an important variable when installing pipes. The added cost of digging down the extra couple of feet needed to make a basement for a house in the Northeast is relatively small, he said. “If you’re that deep, you’re pretty well along forming the shell for the basement.”

But in the Southwest, where the frost line is only about 18 inches below ground, the added incremental cost of digging out a basement would be far steeper, said the Texan.

“Here, houses are typically built by placing a slab on the surface and building above it.”

The making of a nightmare tornado (You Need a Storm Shelter!)

Lessons to be learned

Kiesling is also executive director of the National Storm Shelter Association, a nonprofit group that focuses on improving the quality of storm shelters.

He was planning Tuesday to organize teams to travel to Moore to study which structures failed and which performed well. “There’s a lot of lessons we can learn from this,” he said.

Kiesling said he had heard news reports citing underground shelters as the only safe places Monday in Moore. “That causes my blood to curdle, because I’ve spent my career developing safe places above ground,” he said.

Monday’s disaster is expected to lead to renewed calls to ensure that new houses are equipped with some sort of protection, said Leslie Chapman-Henderson, president and CEO of the Federal Alliance for Safe Homes.

But don’t count on them to effect change.

“What happens is that time and fading memories are the worst enemies,” she said. “People think it can’t happen twice, but in the case of Moore, Oklahoma, the tragedy here is this is the third strike — 1999 to 2003.”

After each of those strikes, homebuilders pledged never again to build homes without including safe rooms, she said. Though many followed through on their vows, more work remains, she noted.

Above Ground Storm Shelters as Effective as Below Ground Shelters

NewsOn6.com – Tulsa, OK – News, Weather, Video and Sports – KOTV.com |

MOORE, Oklahoma –

The massive storm that hit central Oklahoma last week has shined a light on safe rooms and storm shelters.

More than 3,000 shelters are registered in the city of Moore, and the city says everyone who took shelter inside one of them survived the storm.

The violent path of the tornado can be seen everywhere in the Moore neighborhood. Mindy Chaddock and family made it through the over 200-mile-an-hour winds by huddling in a storm shelter.

“People describe it as a train feeling–it wasn’t anything like that. I mean, the whole thing was shaking,” Chaddock said.

The one that saved her family is a below ground shelter; the most common kind of shelter in the neighborhood.

“This storm–I don’t see how you can survive in a bathtub or a closet, because, even in a shelter, we were scared for our life. That’s how strong it was,” Chaddock said.

“We’re looking, right now, for anything that was used to survive the tornado,” said Tom Bennett.

Bennett is a News On 6 weather producer, as well as president of Jim Giles Safe Rooms and past president of the National Storm Shelter Association or NSSA.

Members of that organization have been surveying in Moore, looking at the safe rooms and storm shelters to see how they performed during the tornado.

Complete Coverage: May 2013 Tornado Outbreak

Bennett said they haven’t seen a case, yet, of either an above ground or below ground shelter failing in the storm.

Bennett said while there is some minor damage to some of the above ground shelters, like the turbines flying off or the handles being bent, there’s nothing that would lead to tragedy.

“We’re not seeing anything here that caused injury or death. If you were in a safe room, whether it was above ground or below ground, you survived the tornado,” Bennett said.

Chaddock said she’s thankful to the Chickasaw tribe for installing the shelter for her grandmother and hopes everyone knows how important shelters are, no matter the cost.

“It’s 100 percent worth it. I mean, if you value your life and you value your children’s life, it’s 100 percent worth it,” she said.

Wind engineers from Texas Tech University are also in Moore. They’re reporting to FEMA about what the wind did to all of the structures–the buildings, the schools, even the storm shelters.