The National Oceanic and Atmospheric Administration confirms it: The tornado that hit near El Reno, Okla., on May 31 was the largest one ever recorded in the United States. At its maximum, the storm stretched 2.6 miles and reached the highest level, 5, on the Enhanced Fujita tornado scale. The top wind speed was 296 mph (just shy of the 301-mph record for the fastest ever on Earth).
Below, storm chasers document the formation of the beast, from a multi-twister storm to a wedge of wind so wide it's hard to see it spinning.
How powerful is an EF-5 tornado? Powerful enough to flip a tractor trailer on its side. (Sic on the video description.)