EF-2 and EF-3 tornadoes with 111 mph-165 mph winds can destroy a property in four seconds. The biggest initial risk to properties is flying debris, which can shatter windows and other openings and create holes in exterior walls. Once an opening is created, air rushes inside the structure and pressurizes it like inflating a balloon. The internal pressures build up and put pressure on ceilings and the roof, which is also getting uplift pressures from external wind forces. If the connections between the roof and walls are weak, these wind forces will drive the roof and walls to give way. Once the roof blows off the entire structure can collapse within seconds. Houses and businesses are not typically designed to withstand the impact of a severe tornado. However, options for improving structural performance do exist and can produce effective results, particularly when combined with the use of a safe room. Widespread use of effective strapping, which might increase the cost of a wood frame house by two percent, would create houses that are significantly more resistant to all kinds of severe wind events.
Not all severe weather is alike. Why should your reactions be alike?
IBHS experts offer guidance for protecting lives and properties in tornado-prone areas.
Everything you need to know about creating a stronger, safer roof for your home or business.
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Tornadoes: Make a plan, take action and set an example for others.
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