The National Weather Service has just upgraded the May 31 El Reno, Union City, Okla., tornado to an EF-5 with a width of 2.6 miles wide, making it the widest tornado ever documented.
EF-5 is the highest possible rating for tornadoes on the Enhanced Fujita scale.
The upgrade was based on information from OU RaxPol Doppler data or mobile radar data, that measured low level winds of 296 miles per hour.
The National Weather Service said some of the subvortices had a forward movement of up to 180 miles per hour.
This tornado is double the width of the May 20 tornado in Moore, Oklahoma.