A tornado is not a hurricane. It's a much fiercer storm. The smallest tornadoes have winds as strong as the very worst hurricanes, and so it's long been thought that a house doesn't really stand a chance against a direct hit by a tornado. The best we can do is build safe rooms--reinforced bunkers buried in the house where occupants can hunker down, and at least walk away from the disaster. While that remains largely true, recent research led by Andrew Graettinger from the University of Alabama shows that most of the homes destroyed by the devasting tornado that roared through Moore, Okla., in 2013, and earlier tornadoes in Tuscaloosa, Ala., and Joplin, Mo., in 2011, might have survived if built to standards now adopted in coastal communities to resist hurricanes.
The researchers confirmed that light-frame wood structures cannot withstand a direct hit from an EF4 or EF5 tornado. However, the research showed that some 85% of the damage area left behind by an EF4 or EF5 tornado experiences winds less than 135 mph - in the realm of hurricane force winds. And we know how to build against those forces. In fact, it's work that can be done on homes at the time the roof is replaced. (See Coastal Contractor, "Strengthening Roof-to-Wall Connections").
"There are some simple things you could do to keep your house together," said lead investigator Andrew Graettinger. This includes not only strengthening the roof-wall connection, but also reinforcing the garage door. Once the large and vulnerable door of an attached garage is breached, it can pressurize the interior of the home and literally blow the roof off the house (see Coastal Contractor "Soundings: Garage Door Recommendations"). Of course, safe rooms and shelters are still needed to save the lives of those in the direct path of a tornado (see Builder, "How to Build a Tornado Safe Room").