**UNLESS AVAILABLE/SOURCED FROM A GOVERNMENT WEBSITE OR GIVEN OUR EXPLICIT PERMISSION, NO IMAGES OR OTHER MEDIA FROM THIS SUMMARY ARE TO BE REDISTRIBUTED IN ANY WAY. SOME OF THIS MATERIAL WE HAVE OBTAINED UNDER VERY SPECIFIC PERMISSIONS TO FEATURE. WE WILL TAKE ACTION IF ANY REPOSTINGS OR REDISTRIBUTIONS ARE FOUND OF THE FOLLOWING SUMMARY CONTENT.**
One of the most powerful tornadoes in known history occurred during the May 24, 2011 outbreak. This extraordinarily violent twister took nine lives over a 65-mile path. Yet, even with all the accompanying tragedy, this was also a nearly unrivaled success story in terms of public preparedness. The many damage feats caused and the behavior of this event are both historic. In this summary, we cover every aspect of the maelstrom in as much detail as possible and bring light to the amazing stories that accompanied it.
This work would not be possible without the generous aid of many contributors. First, I cannot thank Rick Smith enough for all of his correspondence and the jaw-dropping amount of material he was able to pass along. Much of the analysis and damage observations in the summaries of this twister would be incomplete or impossible without him. A huge thanks to Jim LaDue, Jeffrey Snyder, and Jana Houser for their invaluable input and permission to feature some of their images. Kenny Baker provided an incredible interview, and Davi Porter also was a great help with other Cactus 117 correspondence. Thank you to David Young for sharing his story and pictures with us. Matt Ordower was an especially helpful resource who provided photos, videos, and other information regarding his chasing experience that day. Finally, thank you to Laban West, Steven Smith, John Paul Poirier, Tyler Russ, Sage Mauldin, Charlie Haag, Tim Hutto, and the Oklahoma Mesonet for permission to feature their images.
Summaries
Calumet/Cactus 117 (El Reno Part I) EF5 Tornado – May 24, 2011
(Premium Summary)
Cactus 117-Guthrie (El Reno Part II) EF5 Tornado – May 24, 2011
(Premium Summary)
Statistics
There are some figures regarding this tornado that may never be known. For example, the full monetary cost does not appear to have been publicly released, so all official databases list $0 in damages. Based on what is known about many of the homes destroyed, the expensive disruption of the Devon Plant’s operations for several months, and the destruction of Cactus 117, the total price tag was probably in the range of $100 million. There was at least one satellite tornado, and another mesocyclonic twister that merged with the original vortex. The maximum width found was 2,040 yards (1.16 miles), and the path length, accounting for all twists and curves, was 65.27 miles. The duration was approximately one hour and 49 minutes. There were nine direct fatalities and 181 injuries.
Using an enormous variety of resources, I was able to map the damage swath by EF-scale values and trends. It is very important to note that while some ratings (including most higher-end ones) were derived from what was already documented by the experts, a large portion is from my evaluations. The polygon mapping does incorporate all known information from surveyors, but it is NOT official material. Instead, the various swaths are my best attempt at showing the trends of any viable contextual evidence.
Here are some unofficial damage statistics I compiled during the mapping process:
Total residences: 567
Total non-residential structures (mostly outbuildings): 423
Residences rated EF0: 236
Non-residential structures rated EF0: 194
Estimated area that experienced at least EF0 tornadic windspeeds: 29,410 acres (46 square miles)
Residences rated EF1: 135
Non-residential structures rated EF1: 95
Estimated area that experienced at least EF1 tornadic windspeeds: 16,692 acres (26.1 square miles)
Residences rated EF2: 106
Non-residential structures rated EF2: 53
Buildings rated EF2+: 66
Estimated area that experienced at least EF2 tornadic windspeeds: 9,146 acres (14.3 square miles)
Residences rated EF3: 46
Non-residential structures rated EF3: 8
Buildings rated EF3+: 14
Estimated area that experienced at least EF3 tornadic windspeeds: 4,409 acres (6.9 square miles)
Residences rated EF4: 35
Non-residential structures rated EF4: 0
Buildings rated EF4+: 2
Estimated area that experienced at least EF4 tornadic windspeeds: 1,454 acres (2.3 square miles)
Residences rated EF5: 0
Non-residential structures rated EF5: 0
Estimated area that experienced EF5 windspeeds: 257 acres (0.4 square miles)
Tornado Path
Corrected Coordinates Based on Analysis of Ground Level, Aerial, and Satellite Imagery, as well as all Reliable Damage Reports:
Start: 35.439117/ -98.287081 End: 35.907325 / -97.343810
Note: Exact tornado path may not be straight and/or continuous.
SPC Coordinates:
Start: 35.444/ -98.287 End: 35.921 / -97.356
Note: Exact tornado path may not be straight and/or continuous.
A KTLX Doppler Radar Loop of the tornado.
The Reality of the Rating
The process by which this tornado was rated has been a source of misunderstanding and controversy. The event has been unfairly used to criticize the National Weather Service (NWS) and numerous other tornado ratings. Following countless twisters, the single-minded focus and even obsession by many on the EF scale has wrongfully taken attention away from the victims. A tornado cannot be understood or even begun to be grasped through a 0-5 scale; each is unique and composed of extraordinarily complex dynamics and factors. For these reasons, Tornado Talk typically attempts to avoid highlighting any rating issue that is small or meaningless. The El Reno 2011 case is too important to overlook, and this section is here to set the record straight. The overarching issue arose after the inaccurate Public Information Statement (PNS) shown below was released.
In order to provide the facts of the actual reasoning, I reached out to Rick Smith, the Warning Coordination Meteorologist for the NWS in Norman, and Jim LaDue, a renowned NWS Meteorologist and damage surveyor. They were instrumental in the process of designating this tornado an EF5. Both their responses and information from the report Overview of the 24 May 2011 Tornado Outbreak by Ortega et al. act as proof of the real argument behind the EF5 designation.
It is true that there were no EF-Scale damage indicators (DIs) found that could be rated EF5. Like with the April 27th, 2011 Philadelphia EF5 (and arguably the Rainsville, AL-GA EF5 of the same day), there were simply no residences in the area capable of truly withstanding EF5 winds. The issue was the context; to put it bluntly, this was among the most violent tornadoes ever seen in modern times. The feats were numerous, varied, nearly beyond comprehension, and covered anything from vegetation to mobile radar values to even a drilling rig.
Many NWS offices would leave the rating at the failure rate of the highest engineered structure, and according to the EF-scale, this is still entirely acceptable (and has been done on many occasions). In this case, as Rick wrote in an email, they had on hand an “all star team” of the greatest experts alive. This included the likes of Jim and also, among others, people like Tim Marshall. The backbone of their deliberations regarded whether the context was sufficient to give a highest-end rating despite the lack of EF-scale indicators. Given the people on hand, there was a higher confidence level than usual for any agreed decision. Listed below is a conclusive summarization of the main points involved in the EF5 designation. More details on these feats, other extraordinary, EF5-level occurrences, and incredible imagery of all these things can be found in the detailed chronological summaries.
- Extraordinary destruction at the Cactus 117 drilling rig site, some of it unprecedented (the many feats at that location and more can be found in Part 1)
- The devastation at Calumet Industries
- Extreme scouring of grass and wheat
- Consistent occurrences of total tree debarking with even the most resilient species
- Multiple cars shredded down to unrecognizable pieces and other large steel objects that were hurled exceedingly impressive distances
- Some consideration of expertly analyzed RaXPol radar data in conjunction with the aftermath
SPC Stats
Path length: 63.1 miles
Width: 600 yards
Fatalities: 9
Injuries: 181
Rating: EF5
County: Canadian, Kingfisher, Logan
Other Discrepancies
There is only one other substantial discrepancy to note. The Storm Prediction Center (SPC), National Climatic Data Center (NCDC), and Storm Data Publication (SDP) list a maximum width of 1,760 yards. The survey information and personal analysis indicate a maximum width of 2,040 yards (1.16 miles).
The Future
In Part 1, I discuss how a RaXPol mobile radar collected invaluable close-range measurements of the forming tornado. This data spawned about a dozen research papers, some of them quite prominent in today’s academic tornado literature. There were other scientific advancements that came about in part from this event. Dr. Leigh Orf is widely known for his cutting-edge work in model simulations. For several years, he labored and eventually succeeded in creating first a 30-meter resolution, then a 10-meter resolution (which included 250 billion gridpoints!) simulation of this tornado and its supercell thunderstorm. Two videos, one from November 2016 and a second from January 2020, show the remarkable progress he has made in this area.
In Loving Memory
Near Calumet/El Reno:
Austin Hall, 22
Don Krug, 71
Joan Krug, 67
Miranda Bishard, 16
Terry Peoples, 50
In Piedmont:
Ryan Hamil, 3
Logan Hamil, 15 months
In Cashion:
Billy Leeper, 64
Sharon Dodd, 58
Sources:
May 2011 Storm Data Publication
NCDC Storm Events Database Entry-Canadian County
NCDC Storm Events Database Entry-Kingfisher County
NCDC Storm Events Database Entry-Logan County
Enhanced F Scale for Tornado Damage
Overview of the 24 May 2011 Tornado Outbreak
Performance of residences and shelters in the Oklahoma tornadoes of 24 May 2011
Jim LaDue
Kenny Baker
Rick Smith
Jeffrey Snyder
Ortega, Kiel et al. “Overview of the 24 May 2011 Tornado Outbreak.” American Meteorological Society, 2012. https://ams.confex.com/ams/92Annual/webprogram/Paper201297.html
LaDue, Jim et al. “Performance of Residences and Shelters in the Oklahoma Tornadoes.” American Meteorological Society, 2012. https://ams.confex.com/ams/26SLS/webprogram/Paper211671.html
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