Tornado climatology
Tornadoes have been recorded on all continents except Antarctica and are most common in the middle latitudes where conditions are often favorable for convective storm development. The United States has the most tornadoes of any country, as well as the strongest and most violent tornadoes. A large portion of these tornadoes form in an area of the central United States popularly known as Tornado Alley. Other areas of the world that have frequent tornadoes include significant portions of Europe, South Africa, Philippines, Bangladesh, parts of Argentina, Uruguay, and southern and southeast Brazil, northern Mexico, New Zealand, and far eastern Asia.
Tornadoes of 2013
On May 21, an EF2 tornado touched down near the small community of Glenarm, Ontario about west of Fenelon Falls, and Environment Canada confirmed that the roof of a home was torn off by the tornado and a barn was destroyed. No injuries were reported in this storm. This was Ontario's second tornado of the 2013 season.
A large, slow moving system produced 86 tornadoes across the Great Plains in the last week of May. Many tornadoes, some strong to violent, touched down across Kansas and Nebraska from the 27th through the 29th, with weaker tornadoes recorded in other states. One of the most notable tornadoes of the outbreak was a wide wedge tornado that struck near El Reno, Oklahoma on the evening of May 31. It was the widest tornado ever recorded. The tornado was initially rated an EF5, with estimated winds being measured at > by a mobile Doppler radar; however, the worst damage was rated EF3, thus on August 30, 2013, the tornado's rating was downgraded to EF3. Eight deaths were attributed to this tornado including four storm chasers; TWISTEX project leader Tim Samaras, his son Paul, fellow chaser Carl Young, and amateur storm chaser Richard Charles Henderson. That same evening, a large EF3 tornado moved through several St. Louis suburbs, resulting in major damage and two injuries. In total, the outbreak resulted in 93 tornadoes.