On a windy day, when the wind comes into an open window of your house, the curtains are blown inward. Occasionally, however, a gust of wind which does not come through the window makes the curtains go out through the window (or up against the screen). This occurs even though there are no other windows open in the house (so the wind isn't blowing through the house in the opposite direction). Explain what could account for this behavior. Can you use the same reasoning to explain why a roof gets ripped off a house during tornadoes and hurricanes?