Is your home tornado-proof? - Macleans.ca

Is your home tornado-proof?

Everybody talks about tornadoes, but nobody does anything about protection

by

Canadian Press

Last week, a powerful tornado ripped through the town of Midland, Ont., knocking down trees, tearing up power lines, and tossing mobile homes through the air. In the half-hour it lasted, about 40 homes and businesses were destroyed, and another 75 were damaged. Almost 20 people were treated in hospital for injuries, some due to flying debris. Gregory Kopp, a University of Western Ontario professor who studies the impact of severe wind on buildings, sent two senior students to survey the damage. “It looks pretty bad, actually,” he says. “Mobile homes tend not to do well in windstorms.”

It’s a well-worn joke that tornadoes go looking for trailer parks. But other buildings are vulnerable, too, and Kopp can’t understand why homeowners do so little to protect themselves, even in places like Kansas, which is at the heart of so-called Tornado Alley.

“People just accept it as an act of God, but it’s not,” says Kopp, a mechanical engineer. “With every tornado, we see the same kinds of damage over and over again. I believe we can stop it, and for not too much money.”

A tornado’s strength is defined by what it destroys, since actually measuring its wind speed can be difficult or dangerous. In Midland, a damage survey revealed it to be an F2, with peak winds of up to 240 km/h. (The Fujita scale, which measures tornado intensity, runs from zero to five.) So far, Canada’s had only one confirmed F5, three years ago in Elie, Man. That tornado was so powerful it literally blasted the bark off trees, but luckily, no one was seriously injured.

It’s a far cry from the infamous Edmonton tornado of 1987, an F4 that left 27 dead and injured hundreds more. The Prairies are Canada’s most prone region, according to Environment Canada; Saskatchewan averages 12 tornadoes per year, but Ontario isn’t too far behind, with 11. (The entire country sees about 50 in a year.) Still, the exact number of tornadoes across the country isn’t known, because some strike in unpopulated areas, where no one’s around to notice them. Thanks to urban sprawl and a warming climate, experts say more damaging storms could be on the horizon. “In Tornado Alley, they get huge numbers of tornadoes,” says Gordon McBean, another UWO professor and policy director at the Institute for Catastrophic Loss Reduction, which studies disaster prevention. “As the climate shifts northward, will we get more of those? As a risk manager, I say yes.”

At the UWO, a leader in wind research, Kopp oversees the Insurance Research Lab for Better Homes, also known as the Three Little Pigs Project. In his team’s lab, a full-size, two-storey house has been built; in August, it will be ripped apart by a simulated windstorm (essentially “fancy vacuum cleaners that suck the roof off,” he says). A house’s roof is especially vulnerable in a tornado, where the wind can gust vertically. In 2012, the UWO will open a new wind research facility called the WindEEE Dome, the world’s first hexagonal wind tunnel; it will actually be able to recreate high-intensity systems like tornadoes.

To save houses from destruction, Kopp thinks that low-cost add-ons could make a huge difference—like wind-resistant nails, which are shaped like screws, or hurricane straps, thin pieces of metal that hold the roof in place. In most Canadian buildings, “the roof is simply nailed to the wall,” he says. He’s looking at new wall and window systems that might help prevent storm damage, too. He hopes his research will ultimately help bring about changes in the building code.

Still, “it’s almost a psychological question, more than engineering,” he says. “People would rather show off nice granite countertops than brag about a tornado-proof house.” If McBean is right, and more storms are on the way, that could change fast enough.