Killer El Reno Tornado Was Widest Ever Recorded: NWS
                                  
- Published: June 4th, 2013 
 
                                    By 
Andrew Freedman                                 
                                 Follow @afreedma                            
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          The tornado that struck El Reno, Okla., on May 31 was an EF-5 twister,  the strongest on the Enhanced Fujita Scale, the National Weather Service  reported on Tuesday. The tornado had a stunning width of 2.6 miles,  which makes it the widest tornado on record worldwide. 
The twister  killed 13, four of whom were storm chasers, 
including pioneering tornado researcher Tim Samaras.
      The width of the tornado was equivalent to the entire north-south  length of New York City's Central Park, which extends 2.5 miles from  59th street in Manhattan to 110th street.
                                                                                                                                                                 
	
	
	
		
		
		
		
	
	
                                                                                 View of the El Reno tornado from KFOR-TV in Oklahoma City.
    Credit: KFOR.com                                                                                               
      The massive size, and the tornado's rapid expansion, plus damaging  winds that rotating around the edges of the tornado all likely played a  role in catching so many tornado chasers and motorists offguard.
      The NWS had initially rated the tornado an EF-3 after 
viewing damage on the ground, but the upgrade was made after examining radar data from mobile Doppler radars that were in the field observing the tornado.
      The NWS statement said:
      "The tornado has been upgraded to an EF-5 tornado based on velocity  data from the research mobile radar from the University of Oklahoma  RAX-POL Radar. In addition... the width of [the] tornado was measured by  the mobile radar data to be 2.6 miles after the tornado passed east of  U.S. Highway 81 south of El Reno."
                                                                                                                                                                   
                                                                                     
	 
                                                                                                                                                                        The path and width of the El Reno tornado.
    
Click on the image to enlarge. 
    Credit: NWS                                                                                               
      "This width is the width of the tornado itself and does not include the  damaging straight-line winds near the tornado as determined by the  high-resolution mobile radar data. The 2.6 mile tornado path width is  believed to be the widest tornado on record in the United States."
      The radars measured winds of close to 300 mph associated with the  tornado, according to tornado researcher Howard Bluestein, quoted on the  
Washington Post's Capital Weather Gang blog.
      The record width makes the tornado more than twice as wide as the  devastating EF-5 tornado that struck Moore, Okla., on May 20, killing  24. According to the National Weather Service office in Norman, Okla.,  the 11 days from May 20 to May 31 was the shortest time span between  EF-5 tornadoes in Oklahoma history.
      The width of the tornado may explain why this tornado proved so deadly to tornado chasers, causing the 
first deaths ever recorded in more than three decades of storm chasing.
                                                                                                                                                                   
                                                                                     
	 
                                                                                                                                                                        High-resolution radar imagery from the OU RaxPol  mobile research radar, showing different aspects of the El Reno tornado.  In the top left imag the main vortex is located in the center of the  larger donut hole.
    
Click on the image to enlarge.
    Credit: Twitter via 
@WunderAngela.                                                                                               
      According to KFOR-TV in Oklahoma City, the previous record-holder was  an EF-4 tornado that hit Wilber-Hallam, Neb., in May 2004. It had a  maximum width of 2.4 miles. 
      The El Reno tornado killed Samaras, 55, his son Paul, 24, and chasing  partner Carl Young, 45. A chasing crew from The Weather Channel was also  struck by the tornado, with a chase vehicle carrying meteorologist Mike  Bettes and two crew members 
tossed 200 yards off the road. One crew member suffered broken bones and required surgery.
      Tornadoes are rated based on the damage they cause, but Doppler radar  data can also be incorporated into the ratings, as was done in this  case. This raises an interesting issue, though, regarding whether even  wider tornadoes might have been missed during the early years of the  historical tornado record, which extends back to the early 1950s, well  before the Doppler radar era.