NORMAN, Okla. -

The National Weather Service in Norman, Okla. is reporting that the El Reno tornado that struck in Oklahoma on May 31st was an EF5 with winds near 295 mph.  The tornado was 2.6 miles wide, making it the widest tornado in U.S. history.  This surpasses the 2.5 mile wide tornado that hit Hallam, Nebraska on May 22, 2004.

According to the National Severe Storms Laboratory, the tornado blew up from 1 mile to 2.6 miles wide in a 30 second time span.

The NWS originally rated the tornado an EF3, but upgraded the rating after surveying the damage. 

The El Reno tornado had a path length of 16.2 miles.  There have only been eight F5 or EF5 tornadoes in Oklahoma since 1950, two of those in the past two weeks. 

The 11 days from May 20th to May 31st is the shortest time span between EF5 tornadoes in Oklahoma history.

Eighteen people were killed in the El Reno tornado including researchers/storm chasers Tim Samaras, his son Paul Samara, and Carl Young.

The stats are still preliminary and could be tweaked as more information becomes available.