El Reno: Lessons From the Most Dangerous Tornado in Storm Observing History

on May 31st 2013 an exceptionally large and powerful tornado formed near eleno Oklahoma up to 2.6 mil in diameter This Tornado produced Winds near 300 mph ranking with some of the most intense tornadoes in history This Tornado exhibited an unusual pinent for changing both speed and direction forward speeds ranged from nearly stationary to over 50 mph while the direction of movement spanned over 360° looping over Interstate 40 this made safe observing at close range almost impossible the high precipitation character of the parent thunderstorm made viewing very difficult for storm spotters and Chasers all of these factors combined to produce an incredibly dangerous situation in which many storm observers were forced to flee for their lives unfortunately not everyone Made It Out Among the eight victims this storm claimed were well-known stormchasers Tim samis Paul samis and Carl Young as well as at least one other storm observ in view of this tragedy we deem it important to document the lessons that this storm has pressed upon the chasing and spotting Community we hope that this documentation will reduce the risk of another such tragedy Friday May 31st severe weather has been in the forecast for days but where and would a tornado threat exist it is early morning forecasters are convinced that a potent combination of atmospheric ingredients will set up over Central Oklahoma tornadoes look likely in an area that has already seen more than its fair share of wicked weather on May 20th a rare EF5 tornado ravaged Moore Oklahoma a suburb of Oklahoma City This Tornado took the lives of over 20 people and left hundreds injured similar to the 20th a large slow-moving upper tropospheric trough is positioned over the plains the southern periphery of this trough features an intense mid to uper tropospheric jet which has initiated strong southerly low-level flow very rich moisture is moving toward the plan ples in the middle troposphere strong Westerly winds are transporting a cool dry layer of air over the warm moist layer to the east the overlap of these two air masses is creating a zone of conditionally unstable air over the Southern Plains and the Upper Midwest conceptually conditional instability is similar to the hot air balloon hot air is less dense than cold air at the same pressure level so the balloon Rises this force is known as buoyancy gravity acts in the opposite direction if buoyancy is greater than gravity an upward force is created instability can be measured from weather balloon data these balloons rise through the troposphere creating a vertical profile of temperature humidity and winds during the early even evening a weather balloon is launched from Norman Oklahoma revealing a vertical profile of the troposphere the environmental temperature with height is in red the parcel temperature analogous to the hot air balloon is the dotted line notice that the parcel temperature is much greater than the environmental temperature this means that air originating from the ground will rise with great force once the environmental temperature is cool enough the total difference in the two temperature traces is known as the convective available potential energy or Cape the area between the two temperature traces determines the value of Cape all of this energy is contained by a warm dry layer of air known as the cap this layer of air originates in the desert Southwest it prevents thunderstorm development through most of the day generally until Peak heating when it breaks it breaks explosively similar to the effect of removing a lid from a Boiling Pot of water the combination of Rich GF moisture with cool dry air above has led to the development of extreme instability Cape values reach as high as 6,000 Jew per kilogram in Southwest Oklahoma a surface low pressure has formed over Southwestern Oklahoma backing the flow in central Oklahoma from South to Southeast in addition to strengthening convergence in Southwestern Oklahoma that may lead to the initiation of thunderstorms this is also increasing the Turning with height in the troposphere leading to Stronger vertical wind shear in the middle troposphere winds are from the west and southwest generally above 40 knots over the Southern Plains combined with the backed surface flow this has led to the development of deep layer Shear more than 40 knots given the extreme instability conditions have become more than sufficient for rotating thunderstorms to illustrate we turn to the Paddle Wheel if water at the top of a Paddle Wheel is Flowing quickly and water at the bottom is Flowing slowly the Paddle Wheel will tend to rotate this effect also occurs in the atmosphere since air is a fluid here is an image from a developing thunderstorm on a day when tornadoes occurred nearby the winds at the top of this towering cumulus are much stronger than at the bottom this causes the developing storm to lean down sheer unseen by the eye are numerous horizontal circulations the formation of supercell thunderstorms from which tornadoes develop begins with these horizontal circulations created by differences in wind speed and direction with height when a developing thunderstorm updraft encounters a circulation the circulation is tilted upward by the updraft into the the shape of a horseshoe this creates circulations spinning opposite directions the northern circulation spins clockwise and the southern spins counterclockwise the wind pattern often favors strengthening of the Southern circulation while the northern circulation tends to dissipate the southern updraft continues to strengthen as an adjacent downdraft forms created in part by precip ation this precipitation is wrapped around the updraft creating the characteristic hook Echo a supercell is Born the stage is set for intense supercells a stationary boundary generated by previous convection is positioned over Interstate 40 in central Oklahoma it is adding fuel to the proverbial fire it is simultaneously enhancing the low-l shear while creating a focus Focus for convective initiation at its intersection with the dry line visible satellite imagery shows partly cloudy skies in central Oklahoma warming the air near the stationary boundary providing power for explosive updrafts it is 400 p.m. the atmosphere is primed for the development of intense thunderstorms radar shows a number of attempts at thunderstorm initiation west of Oklahoma City but as of yet nothing has developed however on the ground cumulus are seen towering High just west of Oklahoma City indicating that thunderstorms will initiate soon stormchasers are beginning to converge in the small town of eleno as the location of key boundaries strongly hints that it will be Ground Zero around 4:30 the capping inversion the layer of B A that often suppresses storm development in the plains breaks in a Northeast to Southwest line line about 50 Mi west of Oklahoma City several storms rapidly form reaching Heights well above 50,000 ft still considerable uncertainty remains concerning which storm or storms will dominate this storm approximately 15 Mi west southwest of Calumet quickly develops mid-level rotation radial velocity shows a weak but classic rotational signature about 10 miles west of eleno at the ground storm observers note a rapidly rotating wall cloud just south of the interstate the National Weather Service issues a tornado warning unconfirmed reports of a large tornado are hitting the TV Airways just as this storm is approaching maturity another storm develops to its South merges and begins to rotate shortly after 6: p.m. a vigorous circulation develops rapidly 10 miles Southwest of elino from the ground this circulation is seen as another large rapidly rotating wall cloud within 2 minutes of its development a ground circulation develops the alino tornado has begun the tornado immediately shows strong multiple vortex structure The Tempest tour Group is located southeast of the tornado a traditionally safe spot if a tornado is moving Northeast the tornado does not initially appear to deviate from the expected motion to the east it also doesn't appear very close an illusion created by the low hanging Cloud base sub vortices appear as well but instead of moving left to right they appear to move closer to the photographer the tour leader begins to sense danger and signals his tour members to come back to the vehicle the tornado does not appear very large but the entire circulation is almost a half mile across the tourists frantically make their way back to the vehicle as the tornado rapidly closes on their location the two are Center their vehicle and are barely able to escape the widening tornado can be seen from a rear view camera it is about 6:06 p.m. The Tempest tour group is making their escape just south of the tornado meanwhile Brandon Sullivan and Brett Wright are stopped along child's Road just south of Reno Street filming the developing tornado to their West the tornado appears to be a half mile away away which should leave enough time for a safe Escape what they don't realize is that the tornado has expanded to 3/4 of a mile wide and the forward speed has increased to 35 mph the edge of the ttic Windfield is close and closing realizing the danger Sullivan and Wright begin to pack up their gear I got it get in the car then get in the car Sullivan and Wright head south they realize the tornado is much closer and they make a frantic Escape they are overtaken by the outer edge of the tornado they survive without injury meanwhile Dave dmco and Heidi Ferrar are observing the tornado a few miles to the north dmco and Ferrar are in the notch the space in between the large Hail to the North and the tornado to the South the storm is high precipitation in character and so it is difficult to see the tornado especially from the north not knowing the exact size and movement of the tornado they begin to worry about where to go they agree to bail West while dimco and Ferrar are observing the widening Tornado from the north Skip talit and Jen Brindley are observing the approaching Tornado from the East the time is 6:13 p.m. from their location the tornado is difficult to see because of the rain talbet notices very fast moving rain Cur very close and decides it's time to bail East from talit and brinley's location the condensation funnel is faintly visible and occupies the area seen here in blue the visible funnel is approximately. 3 Mi wide the tornado width based on mobile radar data is about 1.6 mil in diameter noted by the red circle thus the area occupied by the full tornadic Windfield is is more than 10 times larger than its condensation funnel in this modified version of Talbot's video you can see how large the tornado Windfield is compared to the condensation funnel now realizing the imminent threat talbet and brenley Retreat East on 15th Street the tornado keeping Pace at a blistering 45 mph while they are fleeing Ray bohack and his crew are following the tornado on Reno just a few miles Northwest of talbat in Brinley they watch as the large tornado intensifies in front of them it is 615 the tornado was difficult to see and shrouded by rain and debris suddenly two more tornadoes appear satellites these tornadoes are 1/4 to 1/ half mile from from the edge of the main tornado these tornadoes spin about the main funnel in a counterclockwise orbit it is 618 a Weather Channel crew led by Mike Bettis is racing South down Highway 81 meanwhile Richard Henderson is trying to beat the tornado to the east his progress delayed by a chaser traffic jam near the intersection of 15th Street with Highway 81 the tornado appears as a wallet condensation Mikey Gribble shoots video to the West along 15th Street as The Weather Channel crew is frantically attempting to get past the tornado a mile to his West they do not make it while the weather channel is attempting to outrace the tornado Richard Henderson continues East on Reno hoping to beat the tornado to the east hindered by the blinding rain and powerful winds Henderson stops with brutal force the tornado overtakes him he does not survive the lead car of The Weather Channel crew is hit by a sub Vortex within the larger tornado and their vehicle is rolled almost 200 yards the car is badly damaged and all airbags are deployed amazingly all of the team's crew members have survived as The Weather Channel crew is getting hit Dan Robinson is heading East on Road just west of Highway 81 he briefly considers heading south but realizes there isn't enough time the tornado is moving fast much faster than expected Robinson decides to continue heading East on ruter unknown to Robinson at the time a white Chevy Cobalt is following him in it are Tim samaris Paul samaris and Carl Young though the main condensation funnel is still a mile away Robinson is overtaken by the invisible edge of the tornado Robinson's four-cylinder vehicle struggles to go Eastward against strong East and northeasterly winds the wind slows down Robinson's attempt to escape the approaching tornado less than a half mile behind Robinson a powerful sub Vortex is swinging Northwest toward Rutter in the direct path the twistex crew is riding out the storm alongside the river Ro near a creek The Vortex briefly stalls over their Chevy Cobalt it tumbles over five times they do not survive the tornado continues to head north the forward speed of the tornado slows down to less than 10 mph the tornado becomes increasingly wrapped in Rain meanwhile at 6:41 skip talot spots another tornado approximately 5 miles to the southeast of the main tornado This Tornado though is spinning clockwise or anticyclonically though only a couple yards in diameter This Tornado is powerful with Peak winds approaching 150 mph finally at 6:43 p.m. the tornado dissipates near the intersection of I40 and banner road several lessons have reemerged from this tragic event it is our hope that these will lower the probability of another chasing or spotting tragedy first tornado motion is always unpredictable even for big tornadoes they don't move in straight lines or at constant speed and it's often difficult to tell where a tornado is moving the eleno tornado changed directions over 360° thus if you were close there was no safe spot regardless of what direction the tornado had been moving Additionally the range of speeds in the alen tornado was enormous from nearly stationary to over 55 mph near Highway 81 the tornado doubled its speed from 25 to 50 mph in 5 minutes if you can't see the tornado as was the case with Dan Robinson and the twistex chase team north of the tornado you may be in Mortal danger sudden turns can and do happen tornadoes can expand rapidly from 605 to 610 when Brandon Sullivan and Brett Wright stopped to shoot video along child's Road the width of the tornado doubled from 6 mil to 1.2 mil wide making a close approach to a tornado can be very dangerous and potentially deadly a tornado is often larger than its condensation funnel in some cases much larger skip Talbot's view of the tornado at 613 demonstrates this quite well the tornado appeared to be 1/3 of a mile wide but the tornadic Windfield was well over a mile wide in the case of the twist X group it is quite likely that they thought they had more time to escape the tornado than they actually had since the outer edges of the tornado were not visible however the easterly winds inside the uncondensed tnic circulation were powerful enough to hinder their escape on Rutter resulting in tragedy when big tornadoes occur they are often accompanied by other tornadoes these additional tornadoes present a big problem for those trying to observe storm safely the first type is the satellite tornado at 6:15 p.m. multiple satellite tornadoes were observed on the west and south side of the alino tornado these tornadoes generally occur within a mile of the main tornado in any direction close observers are particularly vulnerable to this type of tornado the second type is the anticyclonic tornado this type of tornado spins in the opposite direction of the main tornado while the REO tornado was wrapped in rain near I40 a powerful anticyclonic tornado with winds up to 150 mph developed to the southeast of the main tornado typically these tornadoes form to the right of the hook Eko a fair distance away from the main cyclonic tornado the final type of danger comes from new tornadoes forming in new circulations within the parent thunderstorm they generally form Downstream of the existing tornado the notch of a high precipitation super cell is extremely dangerous it is why core punching approaching the Tornado from the rain and hail Is So perilous this is the area of the storm immediately to the left of the tornado and just to the right of the large hail those in the notch are in danger of the sharp left turns that tornadoes often make when they are dissipating if the tornado can be seen successful escapes can be made however heavy rain May hide the tornado in that case radar updates may be the only way of knowing where the tornado is located but in the case of the ELO storm the tornado moved 2 miles north in less than 5 minutes less than the interval of a wsr88d volume scan Additionally the radar cannot pinpoint the exact location of the tornado with certainty so you should not depend on radar to know where the tornado is and even if the position of a tornado is known strong INF winds may hinder a quick escape this almost certainly was the case for the twistex team on Rudder Road as mentioned previously new tornadoes are always a danger in the Notch and of course there's the Lesser thread of very large glass-breaking hail in the core of the storm in the path of an approaching tornado a Quick Escape may not be possible a lack of good road options poor road conditions or even TR traffic may hinder a safe escape and in the case of the eleno tornado numerous traffic jams were reported it appears that these traffic jams may have resulted in the deaths of at least three people in three different cars based on these lessons we suggest that storm spotters and Chasers Place more distance between themselves in the tornado especially on days when parameters are particularly volatile when the instability and sheer combination is high the storm Evolution may occur more quickly decreasing the margin for error moreover given the Rarity of the ingredients that produced the alino tornado storm Behavior May differ greatly from more normal tornado days for example on June 8th 1995 a very large tornado accelerated to nearly 60 MPH near Allison Texas before slowing down to nearly stationary you may have seen videos of people who escaped death and serious injury when their vehicles were hit by the eleno tornado but it's critical to remember that in most of these cases the vehicles were not impacted by the strongest winds in the tornado it is possible that this has resulted in a false sense of security within the storm observing Community the most powerful winds in a tornado are located in sub vortices which are smaller tornadoes within the larger circulation these are the vortices responsible for leveling one house but leaving a house next door unscathed given the small area they occupy the probability of being hit is actually rather low however as the number of Close Encounters increase the odds increase that more Chasers will encounter these deadly winds this is especially true now given the growing trend of extreme chasing remember that no footage report or data is worth your life of the eight deaths in the tornado at least four were Chasers there will always be more storms e for

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Length: 25min 47sec (1547 seconds)

Published: Mon Feb 26 2024