Tornadoes can wreak havoc on communities in minutes, tearing apart some homes and leaving others untouched. These destructive forces of nature can toss vehicles upside down, throw them onto buildings and cause a board of wood to pierce right through the trunk of a massive tree. But not all tornadoes are created equally, and meteorologists survey the damage they leave behind and rate twisters to put their damage into perspective. The National Weather Service (NWS) conducts storm surveys to provid