In this week's feature, we tell the story of Tim Samaras, one of the most respected tornado scientists in the country. On May 31, he, his son Paul and chase partner Carl Young navigated back roads southwest of El Reno, Oklahoma, beneath dark, circulating clouds. Just after 6 that evening, as they tracked parallel to a rain-shrouded tornado, it wheeled on them.
As fellow chaser Dan Robinson was pummeled by its outer circulation just a half mile or so ahead of them, he unwittingly captured their final moments with his rear dash cam. Samaras' white Chevy Cobalt was found later that evening, a compacted, unrecognizable hull. Samaras, his son and Young did not survive.
Initially, the National Weather Service classified the El Reno tornado as an EF-3 on a scale of one to five -- five being the most powerful and destructive. It received this designation because the tornado passed largely through the remote farm country. The Enhanced Fujita Scale is based entirely on damage, and with little of it for the survey team to observe, it received a middling rating.
In a move I'm told is unprecedented, NWS upgraded the tornado's rating based on Doppler data collected by the University of Oklahoma's RaXpol mobile radar system, which measured wind speeds approaching 300 mph. The EF-3 became an EF-5.
But the NWS is walking that rating back, according to its annual killer tornado statistics. On Friday, it downgraded the El Reno tornado back to an EF-3.
"Despite the radar-measured wind speeds, the survey team did not find damage that would support a rating higher than EF3," a spokesperson for the National Oceanic and Atmospheric Administration told The Oklahoman. "While the wind measurements from the mobile radars are considered reliable, NWS policy for determining EF ratings is based on surveys of ground damage.
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"NWS is exploring whether policy should change to allow the use of experimental radar data in future EF determinations."
The severe weather community was reacting with a mix of anger and confusion Friday on Twitter , demanding consistency in tornado ratings. It's no secret that the Enhanced Fujita Scale has its shortcomings. It's difficult to apply if a tornado's track lacks damage indicators. (If a tree falls in the woods, does it make a sound?) Or, if a massive, unfathomably powerful tornado tears mostly across wheat fields in the Southern Plains, how do we classify it?
The sad irony of it all is that Carl Young and Tim and Paul Samaras had never actually seen an EF-5 tornado. For all their incredible talent for being in the right place at the right moment in all the vastness of Tornado Alley -- for catching lightning in a bottle by successfully placing sophisticated probes in the paths of oncoming tornadoes -- they'd never seen the biggest, most destructive among them. When they looked out on the tornado bearing down on them that day, it's unlikely they knew they were witnessing the widest tornado on record, soon to be classified an EF-5. But they saw it all the same.
Now, it appears, the EF-5 will have always eluded them.