As of May 16, 2012 the last tornado was two days ago.
As of June 14, 2012, the last cofnriemd tornado in the United States was three days ago on June 11.
Yes, go on youtube and you'll see that video. Just to let you know the last tornado in Dallas was a really long time ago.
The largest tornado ever recorded, the Hallam, Nebraska tornado, struck in 2004, so about 6 years ago.
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 average tornado lasts about 15 minutes, but they can last anywhere from just a few seconds to several hours.
3.5 hours
4 mins
3.5 hours
The Joplin, Missouri tornado of May 22, 2011 lasted 38 minutes.
The Tri-State tornado lasted for 3 hours and 29 minutes.