Greensburg, Kansas was struck by an EF5 tornado on May 4, 2007.
First, it's Greensburg, not Greensboro. That tornado occurred on May 4, 2007.
The Greensburg, Kansas tornado of May 4, 2007 lasted 1 hour and 5 minutes.
Since official record keeping began in 1950 No tornadoes have actually formed in Greensburg, Kansas. However, 1 tornado did strike the town on May 4, 2007. This 1.7 mile wide EF5 tornado destroyed 95% of the town.
The Greensburg, Kansas tornado of May 4, 2007 was definitely a real event. It was the first tornado to be rated EF5 on the Enhanced Fujita scale. This enormous tornado destroyed 95% of the town of Greensburg, killing 11.
Some very large tornadoes that have been recorded includeThe Hallam, Nebraska tornado of May 22, 2004 (the largest ever recorded) at 2.5 miles wide.A tornado north of Greensburg, Kansas on May 4, 2007 at 2.2 miles wide.The Moshannon State Forest, Pennsylvania tornado of May 31, 1985 at 1.9 miles wide.The Yazoo City, Mississippi tornado of April 24, 2010 at 1.75 miles wideThe Greensburg, Kansas tornado of May 4, 2007 at 1.7 miles wide.
There was a tornado in Scotland County, October 5, 2007, around 4:30 in the afternoon. The county is near Memphis, Missouri.
The main positive effect of the May 3, 1999 F5 tornado was a new type of unofficial weather advisory: the tornado emergency. A tornado emergency is more urgent than an ordinary tornado warning. It means that a large and potentially very destructive tornado is threatening a populated area. One case of a tornado emergency's effectiveness was on May 4, 2007 when an EF5 tornado destroyed 95% of Greensburg, Kansas. Despite this the death toll was limited to 11. Countless more lives had been saved.
The largest tornado to hit Kansas appears to have been The F5 tornado that struck several towns on May 17, 1896, killing 25 people. The tornado devastated the towns of Seneca, Oneida, Sabetha, and Reserve, killing 21. It then crossed into Nebraska where it killed 4 more people. At its peak this tornado was about 2.2 miles wide.
The largest recorded tornadoes* in 2013 are as followsThe El Reno, Oklahoma tornado of May 31 (2.6 miles wide)The Woodbury County, Iowa tornado of October 4 (1.48 miles)The Wayne, Nebraska tornado of October 4 (1.38 miles)The Moore, Oklahoma tornado of May 20 (1.1 miles)The Schenectady, New York tornado of May 29 (tied 1 mile)The The St Louis area tornado of May 31 (tied, 1 mile)The Red River Parish, Louisiana tornado of July 27 (tied, 1 mile)The Cleburne, Texas tornado of May 15 (0.98 mile)The Bennington, Kansas tornado of May 27 (0.9 mile)The Shawnee, Oklahoma tornado of May 19 (0.85 mile)*The size of the tornadoes, for these purposes, is measured only in path width, which does not necessarily indicate anything about the intensity of the tornado or the damage it caused.
As of May 4, 2012 the most recent confirmed tornado was on May 2, with possible tornadoes on May 3 and 4. None of these resulted in any deaths.
The Grand Valley Tornado struck at approximately 4:15pm on May 31st, 1985. It was the longest (on the ground) recorded Tornado in Canadian records.