Why Tornadoes Can Be So Destructive to Structures Like Your Home
When houses or other structures are destroyed by a tornado, they are not simply blown down by the high winds: they appear to explode. For many years it was believed that the low pressure of the tornado vortex caused such explosions. According to this theory, if the pressure outside a building drops very quickly the air inside may not escape fast enough (through cracks, holes, and the like) to equalize the pressure difference. The higher pressure inside the building then pushes out windows or whole walls, and the structure looks like it had exploded. Studies of tornado damage have shown that buildings do not actually explode in this manner. Instead, high wind passing over a house roof acts like the air moving over an airplane wing: it gives the roof an upward force or lift which tends to raise the roof vertically off the house. Winds also enter the building through broken windows or doors pressurizing the house as one would blow up a balloon. The combination of these forces tends to blow the walls and roof off the structure from the inside out giving the appearance of an explosion.
Note: At least as early as 1970, building codes for Florida homes required structures to be attacked to the concrete block or other
buried structure by metal "straps" that held the house in place so it could not be lifted as discussed above.
Re: Why Tornadoes Can Be So Destructive to Structures Like Your Home
Bruce, it appears that a subterranean or semi-subterranean house may offer protection from violent storms and tornadoes. Would the air pressure problem, in the event of a tornado, remain the same for a conventional home? Remember the bomb shelters in the 1950s and 60s? I'm thinking I may start digging tomorrow. Just a thought . . . . or perhaps a very :slightly_smiling_face: small, refurbished submarine in a large swimming pool.
