The source of this myth is from the appearance of some destroyed structures after violent tornadoes. When one wall receives the extreme pressure of tornado winds, it will likely collapse . This then leads to a considerable pressure on the three remaining walls, which fall outwards as the roof falls down, creating the impression of a house which has exploded. Damage surveys of "exploded" houses usually show at least one wall which has blown inward. Additionally, if the roof is lifted before any walls fall, the walls can fall in any direction. If they fall outward, this structure can also appear to have exploded.