Tornadoes constitute one of the most destructive weather phenomena present in much of the interiors of continents. The storms that spawn tornadoes are often dangerous in their own right, generating heavy rains, flash floods, and hail. But the tornadoes can be powerful enough to level everything in their path which can be miles wide and dozens or hundreds of miles long.
Sources of Data and Information
Storm Prediction Center (more info) The Storm Prediction Center (SPC) is an agency of the National Oceanic and Atmosperic Administration (NOAA) National Weather Service. Materials available on the website include current weather watches, mesoscale discussions, convective outlooks, six-hour thunderstorm outlooks, and fire weather forecasts; research publications, experimental products and techniques; weather information including watch/warning maps, climatological data, and current radar; and a section on tornadoes. There is also an archive of weather images, and sections on the organization and history of the Center.
The Tornado History Project (more info) The Tornado History Project is a searchable, sortable database of tornado statistics based on official Storm Prediction Center (SPC) tornado records since 1950. Results of your search can be viewed in the form of raw data or on a Google Map. Plus, users can leave comments/share memories of any tornado in the database. Original data can be obtained from the Storm Prediction Center Warning Coordination Meteorologist's Page.
NOAA's National Severe Storm Laboratory (more info) The National Severe Storms Laboratory serves the nation by working to improve the leadtime and accuracy of severe weather warnings and forecasts in order to save lives and reduce property damage. NSSL scientists are committed to their mission to understand the causes of severe weather and explore new ways to use weather information to assist National Weather Service forecasters and federal, university, and private sector partners.
Tornado Climatology (more info) This web page from NOAA's National Climatic Data Center provides a wealth of information on the occurrence of tornadoes in the United States including the when and where they tend to occur, historical records and trends, and a storm events database.
Extreme Weather Sourcebook: Tornadoes (more info) The Extreme Weather Sourcebook is a database maintained by the Societal Impacts Program (SIP) at NCAR of statistics on extreme weather events. The Sourcebook is intended as a resource for researchers, policy makers, the media, and the general public, among other users. This page from the Sourcebook showcases data on tornado damages as total losses for the years 1950-2009 in the United States.
TwisterData.com (more info) TwisterData.com is developed and maintained by storm chasers and meteorologists David Demko and Donald Giuliano. The website provides access to weather model data and graphics which can be used to investigate thunderstorm and tornado initiation and development. The data available is limited to the continental United States.
Ready.gov: Tornadoes (more info) The Federal Emergency Management Agency (FEMA) has developed Ready.gov as a way of disseminating information on the best ways to prepare for various disasters and natural events. The Tornadoes page includes things to do to prepare for a tornado, safety precautions to take during a tornado, and what to expect in the aftermath of a tornado producing storm.