National Weather Service survey teams have determined that the El Reno, Okla. tornado of May 31, 2013 was an EF-5 with maximum wind speeds of 295 mph. The tornado was 2.6 miles wide at its widest, making it the widest tornado in U.S. history. This information is still preliminary, according to the NWS Norman, Oklahoma office. The office might adjust the storm’s statistics as more information becomes available.
This is the same storm that killed well-known tornado researcher Tim Samaras.