May 31 in History
2013 - The widest tornado ever recorded hits El Reno, Oklahoma, USA
At 4.2 kilometres in width, this rain-wrapped, multiple-vortex tornado was the widest tornado ever recorded and was part of a larger weather system that produced dozens of tornadoes over the preceding days. The tornado initially touched down at 6:03 p.m. Central Daylight Time (2303 UTC) about 8.3 miles (13.4 km) west-southwest of El Reno, rapidly growing in size and becoming more violent as it tracked through central portions of Canadian County. Remaining over mostly open terrain, the tornado did not impact many structures; however, measurements from mobile weather radars revealed extreme winds up to 302 mph (486 km/h) within the vortex; these are the highest observed wind speeds on Earth, ahead of the 1999 Bridge Creek–Moore tornado with slightly higher wind speeds. As it crossed US Highway 81, it had grown to a record-breaking width of 2.6 miles (4.2 km). Turning northeastward, the tornado soon weakened. Upon crossing Interstate 40, the tornado dissipated around 6:43 p.m. CDT (2343 UTC), after tracking for 16.2 miles (26.1 km), it avoided affecting the more densely populated areas near and within the Oklahoma City metropolitan area.
-Wikipedia
Photo Caption — Shot of the El Reno, Oklahoma EF-3 tornado near maximum width and peak intensity – Wikipedia