There were many tornado outbreaks in 2011, three of which were unusually destructive.
The first one, from April 14 to April 16 had a duration of just over two days.
The second major outbreak, which was the most destructive, lasted from April 25 to April 28 for a duration of just over 3 days.
The third major event actually consisted of two outbreaks in rapid succession, spanning a total of 6 days from May 21 to May 26.
The Joplin, Missouri tornado of May 22, 2011 lasted 38 minutes.
It depends. There were several major tornado outbreaks in 2011. The most significant lasted just over 3 days, from April 25 into the morning of April 28.
The deadliest tornado outbreak in U.S. history was the one which produced the Tri-State tornado on March 18, 1925. As a whole the outbreak killed 747 people, 695 in the devastating Tri-State tornado, the deadliest single tornado in U.S. history. The F5 tornado cut a 219 mile long damage path through 13 counties in Missouri, Illinois, and Indiana.
There have been thousands of tornadoes in the last 5 years. These are the 3 most notable.The Joplin, Missouri tornado of May 22, 2011. This EF5 tornado devastated Joplin, killing 158 people and costing $2.8 billion. This makes it the costliest tornado in U.S. history, the 7th deadliest, and the deadliest since 1947.The Hackleburg, Alabama tornado of April 27, 2011. This EF5 tornado devastated a series of small towns in northern Alabama along a damage path over 130 miles long. The tornado killed 72 people and cost $1.25 billion. This makes it the deadliest tornado in Alabama history and the 4th costliest in U.S. history.The Tuscaloosa-Birmingham tornado of April 27, 2011. This EF4 (possibly EF5) tornado devastated parts of Tuscaloosa and Birmingham, Alabama, killing 64 people and causing $2.2 billion in damage. This makes it the second deadliest tornado in Alabama history and the second costliest in U.S. history. It briefly haled the title of costliest until the Joplin tornado 3 weeks later. This and the Hackleburg tornado were part of the 2011 Super Outbreak, the largest and costliest tornado outbreak ever recorded.
The "Tri-State Tornado" covered a two-hundred mile wide path from Missouri, across Illinois, to southwestern Indiana. The exact time is unknown but it is estimated to have lasted about three and a half hours. == ==
As of May 16, 2012 the last tornado was two days ago.
The Tuscaloosa-Birmingham tornado of 2011 was on the ground for about 90 minutes.
There is no given duration for a tornado of any intensity, but a tornado as violent as an EF5 will generally last fairly long. Most will likely last for at least 20 minutes. Some may last for well over an hour.
It varies. A tornado warning may last for just a few minutes or over an hour.
3.5 hours
The worst tornado outbreak ocurred across portions of Kansas, Missouri, Illinois, Indiana, Kentucky, Tennessee, and Alabama on March 18, 1925. At least nine tornadoes are known to have happened, with more that probably went undocumented. In total, the outbreak killed at least 747 people. Of those deaths, at least 695 were from a single F5 tornado that tore a 219 mile long damage path across parts of Missouri, Illinois, and Indiana. This storm, the deadliest tornado in US history, is known as the Tri-State tornado.
The Joplin, Missouri tornado of 2011 had a damage path of 22 miles.