Ultimate Tornado is a documentary that first aired on the National Geographic Channel

National Geographic Channel

National Geographic Channel, also commercially abbreviated and trademarked as Nat Geo, is a subscription television channel that airs non-fiction television programs produced by the National Geographic Society. Like History and the Discovery Channel, the channel features documentaries with factual...

 on April 12, 2006. It focuses on several unusually violent tornado events that have occurred in the United States: the Attica, Kansas

Attica, Kansas

Attica is a town in Harper County, Kansas, United States. As of the 2010 census, the city population was 626.-History:Land for the City of Attica was purchased in late June, 1884 and became the end of the Atchison, Topeka, and Santa Fe Railway. The town was incorporated later, on February 16th...

 tornado outbreak, the Pampa, Texas

Pampa, Texas

Pampa is a city in Gray County, Texas, United States. The population was 17,887 at the 2000 census. It is the county seat of Gray County.Pampa is the principal city of the Pampa Micropolitan Statistical Area, which includes all of Gray and Roberts counties....

 tornado, the Jarrell tornado outbreak and the 1999 Oklahoma tornado outbreak. It last examined the possible effects of an F5 tornado hitting downtown Dallas, Texas

Dallas, Texas

Dallas is the third-largest city in Texas and the ninth-largest in the United States. The Dallas-Fort Worth Metroplex is the largest metropolitan area in the South and fourth-largest metropolitan area in the United States...

, postulating that this would be the most damaging tornado in history in terms of damage and loss of life.