They fear that the air pressure outside the building might drop so suddenly that the structure would explode outward. Safety experts know, however, that air moves in and out of most buildings so quickly that air pressure remains nearly equal inside and out, even during a tornado. Open windows do not reduce damage and may even increase it because wind blowing in may hurl loose objects through the air. Tornado damage is often localized. A tornado may demolish one house and leave an adjacent house untouched.
Some tornadoes consist of smaller rotating columns of air called suction spots or suction vortices.
The suction spots revolve around the central axis of the tornado and can inflict tremendous damage to small areas. They make such forecasts using data from weather balloons, satellites, and conventional weather radar. Computers help meteorologists analyze the data and recognize when conditions favor the formation of thunderstorms. Meteorologists use a special type of radar called Doppler radar to look for mesocyclones. This type of radar works because radar waves change frequency depending on whether the objects they bounce off, such as raindrops or dust particles, are advancing or receding.