Central Oklahoma Tornado Intercept: 3 May 1999

For tornado numbers and locations of towns, please refer to this map of the tornado outbreak, adapted from the NWS Norman's damage surveys. This page is separate from the SkyPix gallery, and contains both 35 mm still photos and video frame captures for documentation. All text and images are copyrighted 1999 Roger Edwards. Web design copyrighted 2002 Roger Edwards and Elke Ueblacker. All rights reserved.

Chickasha tornado in its early, wide, diffuse, multivortex phase

Fellow severe-storms meteorologist Rich Thompson and I left Norman at about 4:40 pm, headed SW toward rapid supercell development we noted on visible satellite and radar composite imagery. [I had slept a few hours after a midnight shift; and Rich just got off a daytime mesoscale forecast shift.]

The supercell (map, Storm A) formed under a hole in a cirrus plume, just SW of Lawton. It was well-removed from any discernible surface boundaries; the dryline was several counties to the W. [Months later, Rich and I discovered the probable initiator of the storm: a horizontal convective roll. For details, see this conference paper from 2000.] Before we left, we also noted an area of ACCAS (altocumulus castellanus) buildups which were accreting into a surface-based thunderstorm NE of Altus, just E of the dryline and W of our target storm. This would become our second tornadic supercell (map, Storm B).

Though the SPC Day-1 outlook had been (correctly) upgraded with each update during the day, from SLGT to MDT to HIGH, and Rich issued a mesoscale discussion alerting to the tornado threat in Oklahoma, several potential pitfalls still remainded in our minds. Storm-relative "anvil-level" flow (approxmated by equilibrium level) was forecast to be weak -- indicating HP (heavy precipitation) storm character; but winds were expected to be much stronger below the EL in the mid/upper levels of the storm envronment. Would the anvil from the western storm seed ours, prodding it toward HP also?

The eastern storm wound up fast, producing several tornadoes near Stecker, Cyril and Anadarko (map: tornadoes A1-A5) before we could get to it. We were already hearing awestruck descriptions over the radio by KWTV television storm spotters, still concerned that the storm could go HP, and that we may miss the show if the middle-upper level winds didn't cooperate. Seeding from other storms' anvils, and weaknesses in upper level flow, could allow the storm to recycle precipitation particles, become more precip-efficient, and turn into a giant, amorphously dark HP blob as we had seen many times before. So, on the way down to the storm, pessimism ran rampant that we could possibly see no tornadoes. Little did we know the show was barely starting...and that the most destruction ever visited upon the state of Oklahoma was about to occur. Scientific analysis and observation would give way to amazement, then awe, then the sobering realization of human carnage, frustration...then finally, numb exhaustion.

Between Blanchard and Ninnekah, we made a few bad road decisions, but still managed to get within view of the storm's updraft by the time we were E of Ninnekah. Not HP at all -- it was a large, circular, visibly rotating updraft area with very wide separation between the main updraft region and the precipitation of the vault and forward flank regions. Physical concepts of storm-type evolution were being slam-dunked by this rare, spectacular exception! Storm-relative "anvil-level" flow obviously wasn't representing the tremendous downshear precipitation separation and venting which we were observing under the equilibrium level. The seeding influence from other anvils wasn't mattering either, despite our storm's entrapment in the anvil of the one farther W.

By the time we could see under the base, W of Ninnekah, there was already a furiously whirling wall cloud; and wispy tendrils of cloud material were beginning to dance along the ground beneath. Tornado! And the first of many to come.

The next few hours would give us, by far, the most productive storm intercept ever in our 13 concurrent years of it: the most tornadoes, the greatest variety of tornado shapes and sizes, the most violent and destructive (Bridge Creek, F5 damage, $750 million and counting), and perhaps the biggest (Abell/Mulhall, up to 1.5 miles wide, rivalling Rich's Allison tornado on 8 Jun 1995). The tally: 11 tornadoes, 2 after dark, 2 violent wedges, at least 4 multiple-vortex tornadoes, and 3 separate times when two tornadoes were observed simultaneously. The story will now break down into sections taken from the intercept log, according to tornado chronology....

NOTES:All times are CDT, from tape logs and video subsequently calibrated to Weather Channel time. Vantage locations are plotted on the map, as are paths of the tornadoes themselves.

  1. TORNADO 1 (map: tornado A6)
  2. VANTAGE 1: 3 SSW Norge (Grady County), map: V1
  4. VANTAGE 1 TIME: 1752-1756
  • NOTES: Began as ragged, scuddy, rapidly rotating "wall cloud on the ground" with multiple brief, ephemeral vortices. Consolidated into a fuzzy, fat stovepipe under a very low wall cloud with occasional brief, adjacent subvortices, which were definitely members of the whole tornadic circulation. We drove a short distance N to find a better photographic vantage, maintaining view of the tornado.

    1. TORNADO 1 (map: tornado A6)
    2. VANTAGE 1a: 2 SSW Norge (Grady County), included within map: green dot V1 due to map resolution limitations
    4. VANTAGE 1a TIME: 1802-1814
  • NOTES: Tornado narrowed to a SWward-tilted cone with an intermittent debris fan, briefly losing condensation through a translucent debris cloud. It redeveloped full condensation and then rapidly evolved into a wide, symmetric, vertical, slightly tapered cylinder reminiscent of Hesston KS (13 March 1990) or Seymour TX (10 April 1979), but with a fatter aspect ratio than Seymour. The wall cloud became less prominent during this transition. The tornado maintained big- cylinder form in virtual steady state for several minutes while cruising NE, as a satellite tornado formed to its E (below). Wide angle views show the tornado well-centered under a dark, circular supercell base with long attached tails to the E and SW. At times, it looked like the Hesston tornado welded to the underside of a space ship from Independence Day.

    1. TORNADO 2 (map: satellite tornado A5)
    2. VANTAGE: 2 SSW Norge (Grady County); same as Tornado 1, Vantage 1a, map: green dot V1
    4. VANTAGE TIME: 1813-1814
  • NOTES: Thin, ragged, bent cone formed ~ 1 mile E of the massive cylinder tornado and was clearly a distinct tornadic circulation. It moved toward the WNW and toward the big-cylinder tornado (zoom), then turned NW and orbited the larger tornado (zoom) -- disappearing from view behind (N) of the latter for ~20 seconds. [During this stage, there is a striking resemblance between the large tornado and the classic Erie, MI photo from 8 Jun 1953, published in Flora's Tornadoes of the United States and Grazulis' Significant Tornadoes books. Of course, Erie had no satellite tornado!]

    The satellite tornado emerged as a vertical, narrow, slightly tapered stovepipe to the left (NW-W) of the large tornado. It then widened at the top and narrowed at the bottom -- becoming a tall cone with a small debris fan. The satellite tornado turned S and SE, still moving around the large tornado as the latter disappeared behind trees. Though I uttered "Fujiwara" in video, this was not a true binary, mutually-orbiting vortex: The larger tornado's movement was steady and unperturbed, while the smaller one was clearly the tornado in submissive orbit. Though the satellite tornado did kick up debris, its damage path (which should wind cyclonically NW-SW-S-SE) is almost completely masked by that of the larger and obviously much stronger tornado. Both were moving across open country and doing little structural damage during the satellite tornado's existence. Paul Janish was with us for much of these two tornadoes, as were unknown others.

    The next time we could see clearly under the meso was looking N and NNW from the S periphery of Chickasha (map: green dot V2) -- and there was no condensation or debris underneath despite very rapid cloud base rotation. During this time, we got stuck in a small chaser-induced traffic jam for a few minutes as the wall cloud loomed to the NNW. Though the cloud-base meso was visually continuous with that of the next tornado, we believe the twin tornadoes themselves to be separate from the next tornado (the Bridge Creek- Moore wedge). NWS damage survey results support this separation near Chickasha. We believed there could be damage in Chickasha, and wanted to avoid being part of another such traffic blockage. We decided to circumnavigate the town to its S and E using unmarked section roads. We also deliberately avoided I-44 with its limited access, concerned the meso could either be cruising right up the freeway or crossing it at an oblique angle with little escape option.

    1. TORNADO 3 (map: tornado A6)
    2. VANTAGE: 2.5 WSW Tabler (driving N then NE) to 1 NE Middleburg (Grady County). Not plotted on map.
    4. VANTAGE TIME: 1825-1837
  • NOTES: By doing that SE Chickasha detour, we missed the start of this massive wedge tornado by a few minutes; but had an uninterrupted view of it distant NW-N through this drive and the subsequent stop...

    1. TORNADO 3 (map: tornado A6)
    2. VANTAGE: 1 NE Middleburg (Grady County), map: green dot V3
    4. VANTAGE TIME: 1837-1852
  • NOTES: In the preceding driving segment and for this stationary vantage, the contrast was poor. However, we had a long-duration view of both sides of this enormous tornado, surrounding storm structure, and massive/hard convective towers above the flared supercell base. The whole time, the shape and appearance was almost steady-state as a wedge with an aspect ratio of about 4 wide to 1 tall. A slight clear slot became visible to the near left of the giant tornado (zoom), indicating the occlusion downdraft. Bobby Prentice (NWS/FAA Academy) was beside us for much of this vantage. While observing the wedge, we noticed a tilted "barber-pole" storm distant WSW and could see a low wall cloud under the N portion of its base...

    1. TORNADO 4 (map: tornado B3)
    2. VANTAGE: 1 NE Middleburg (Grady County), map: green dot V3
    3. LOOKING: distant WSW
    4. VANTAGE TIME: 1850-1852
  • NOTES: It became apparent the giant tornado now to our N was going to move into the metro area (both by our estimation and all the TV coverage being broadcast on the radio). We were trying to decide whether to go NE thru Newcastle on US 62 and go for the close-up crossing shot, or break off and head for the new supercell. We were on high ground and had a great view (for being so distant) up the Washita valley. A cone tornado appeared under the center of the distant western storm with condensation fully to ground; so we decided not to mess with the big tornado entering the metro area and headed W. We could see the distant western tornado for part of the drive, also...

    1. TORNADO 4 (map: tornado B3)
    2. VANTAGE: 1 NE Middleburg - 2 NE Tabler (Grady County). Not plotted on map.
    4. VANTAGE TIME: 1852-1857
  • NOTES: This was the same tornado near Ft. Cobb of which Jim Leonard (jmlcat-5@ix.netcom.com) was shooting spectacular, close-up, front-lit footage -- perhaps the best white- tornado video I have ever seen. The top part of the "cone" visible to us turned out to be a dense, diagonally striated, helically ascending collar of accreting scud -- corkscrewing around the top of the tornado and brilliantly front-lit in Jim's video. The tornado itself was a tapering elephant-trunk shape. At 1857, it got too narrow for us to see from this distance. We watched a new updraft base develop, also with a wall cloud on the N end (reminiscent of Spearman), but without any apparent tornado, as we drove thru Chickasha and W to Verden. In transit, we somehow failed to see brief tornadoes B4 and B5 (map).

    1. TORNADO 5 (map: tornado B6)
    2. VANTAGE: 3.5 N Verden (Caddo/Grady County line), map: green dot V4
    3. LOOKING: NW
    4. VANTAGE TIME: 1922 [EST. TORNADO LOCATION DURING VANTAGE: near northern Chickasha Lake, ~7 ESE Gracemont (Caddo County)]
  • NOTES: Short (less than a minute), multiple-vortex spinup under a vigorously rotating wall cloud (much more apparent in motion on video than in this freeze frame!). Condensation connecting cloud base to ground very briefly appeared.

    1. TORNADO 6 (map: tornado B7)
    2. VANTAGE: 3 E Dutton OK (Grady County), map: green dot V5
    3. LOOKING: NW
    4. VANTAGE TIME: 1934
  • NOTES: Possibly multivortex spin-up with condensation briefly to ground level, under the central portion of a rotating wall cloud (no stills or video). This was the last of six tornadoes in Caddo County from this supercell. Mike Kay (SPC), Matt Crowther and Betsy Abrams (TWC) joined us at this overlook. The wall cloud subsequently had a classic, nicely cut clear slot around the S side. It became quite elongated E-W, with intermittent wispy funnels and possibly brief ground-level spin-ups under its center. AFter several minutes, the east-central portion of this stretched wall cloud (definitely a separate circulation core and possibly a new occlusion in tight quarters) later began rotating furiously...

    1. TORNADO 7 (map: tornado B8)
    2. VANTAGE: 3 E Dutton OK (Grady County), map: green dot V5
    3. LOOKING: NW-N
    4. VANTAGE TIME: 1937-1940
  • NOTES: Began as intermittent filaments of condensation, then condensed into a fuzzy cone tornado (video zoom). Quickly acquired classic multiple vortices before enlarging into a bowl-shaped tornado -- almost in the form of a wedge.

    We decided to maneuver NE and were unsure at the time whether this was a separate event from our next tornado sighting. It was. While driving, Jim Leonard was shooting video of this tornado to his SW-WNW beginning near the time we lost sight of it. It narrowed and dissipated 4 W Minco and based on his footage, was a clearly separate event from the next tornado. The next tornado formed from a new occlusion area ~ 2 ESE of the dissipation of the prior tornado to his WNW.

    1. TORNADO 8 (map: tornado B9)
    2. VANTAGE: 5 NE Dutton OK (Grady County), map: green dot V6
    3. LOOKING: NE
    4. VANTAGE TIME: 1952-1958 EST. TORNADO LOCATION DURING VANTAGE: 4 WSW Minco to 2 NW Minco (Grady County)
  • NOTES: We first saw this tornado as we topped a hill driving N, about 3/4 mile S of this point. It was slightly bent, and shaped like a widened automotive funnel (as illustrated in this slightly blurred zoom view and a 50 mm slide), with occasional subvortices whipping around in its base. [Jim was less than a mile W of it at the time, shooting close- up footage.] It contracted some into a true cone, which was protruding from an increasingly well-defined wall cloud. The tornado then became swollen with multiple large vortices. While we were watching this tornado to our NE, a separate one briefly formed and did damage just to our N...

    1. TORNADO 9 (map: tornado B10)
    2. VANTAGE: 5 NE Dutton OK (Grady County), map: green dot V6
    3. LOOKING: NE
    4. VANTAGE TIME: 1955
  • NOTES: A narrow, white, fuzzy cone funnel formed about a mile to our N, unroofed a house, then quickly dissipated. We don't know why this tornado developed where it did -- along the convergence boundary trailing the big tornadic meso to our NE. It had obvious condensation and was *not* a gustnado.

    Meanwhile, the better-organized tornado still to our NE narrowed into a cone and faded into the distance. The time given for our last view of it (1958) was probably not its end. Stymied by a police roadblock 2 S Union City on US 81, we had to detour all the way to OK 37 and I-44, then N thru western OKC, before finally catching up with this supercell again after dark near Cashion. In the meantime, we had missed map tornadoes B11-B15 and B17. Storm observing after dark can be very dangerous; but with our combined experience and knowledge of supercell morphology, we felt quite confident we could remain in safe places.

    1. TORNADO 10 (map: tornado B16)
    2. VANTAGE: 4 E Cashion to 1 E Cashion (Logan County), driving W toward Cashion; included within map: green dot V7 due to map resolution
    4. VANTAGE TIME: 2119-2122
  • NOTES: This was the last few minutes of the Cashion tornado, which by radio accounts had been a "wedge" earlier in its lifespan. We first saw it as a cone tornado occasionally silhoutted by lightning, and watched as it narrowed and dissipated while we were finding a suitable pull-off. No video or stills.

    1. TORNADO 11 (map: tornado B18)
    2. VANTAGE: 1 E Cashion (Logan County), map: green dot V7
    4. VANTAGE TIME: 2125-2130
  • NOTES: While observing the old dying meso from the Cashion tornado, we noticed a rotating base and conical lowering in the new occlusion area NE. A cone tornado appeared and quickly (in less than a minute) grew to a wedge, as evident in several video frames. A wide-angle video frame shows classic supercell structure with an enormous wall cloud and attached tail (looking NE), silhouetted by lightning in the forward-flank region beyond. This would become the Crescent-Mulhall tornado. [One slide came out of the early cone tornado with a CG lightning strike well off to its right. It will be scanned after enlargements are done.] We decided to get NE to a better spot.

    1. TORNADO 11 (map: tornado B18)
    2. VANTAGE: 2 E Cedar Valley (Logan County), map: green dot V8
    3. LOOKING: NNW-N VANTAGE TIME: 2147-2151
  • NOTES: Based on NWS damage survey reports, the tornado was continuous from the previous stop thru this one. We could now see an even larger wedge -- aspect ratio ~5 wide to 1 tall (greater than that of Bridge Creek). It was mostly very faintly backlit by lightning -- too faint to show up on video -- but just enough to make out both sides using our eyeballs. Based just on the history of supercells and tornadoes we had seen, we suspected this was a violent tornado, like Bridge Creek/Moore, as did TV chasers and other spotters who also were tracking it. We saw a quick burst of 4 bright, pin-point power flashes at 2148, probably as it crossed OK 74C to our N (E of Crescent), then a fainter power flash at 2149. [The fainter flash was in the direction of the unincorporated hamlet of Abell (not on map), and was, sadly, probably the farmstead at which the first of two fatalities occurred with this tornado...the second being a vehicle blown from under an I-35 bridge near Perry.] The tornado was too wide for either edge to be illuminated by these power flashes! We began to be rained on from the next supercell to our SW, and lost view of the gigantic tornado to the N before it hit Mulhall.

    Later DOW analyses by Josh Wurman of OU would show that embedded subvortices of this enormous tornado were larger than the entire Spencer SD tornado of 30 May 1998, which I also witnessed and which a DOW also scanned. Re-analyses of the damage and storm videos by NWS Norman later would combine the Mulhall tornado's path with that of the Perry event on I-35, giving it the longest continuous track of the outbreak. Though we may never know because of a relative lack of substantial structures to damage during much of its path (especially at its largest, SW of Mulhall), it is quite possible that this tornado was at least as violent as the Bridge Creek/Moore F5, despite its F4 damage rating.

    We briefly attempted to view the next supercell coming NNE out of El Reno -- one which would later produce tornadoes in the area where we were; but poor visibility and the late hour compelled us to head back. I had a midnight shift that night; and it was time to abort the intercept.

    One of the most unforgettable sensations in my entire life -- much less my history of storm observing -- occurred as we were driving S into northwestern Oklahoma City. The unique and pungent aroma of natural gas, combined with shredded vegetation, became very strong. We realized we were smelling the scent of devastation, carried on warm southeast breezes for 10-15 miles from the Bridge Creek/Moore tornado's swath across the southern OKC metro area.

    We were blocked by traffic jams on I-35 (the shortest way back) and I-240 (via Sooner Road, the next shortest). We heard that the I-44 route was still open; so we doubled W and came back through Newcastle -- making it back just before the start of my forecast shift. With duty calling, and a dental appointment at 8:30 the next morning, and lingering adrenaline, it would be after 11 a.m. on the 4th before I would fall asleep in an exhausted state of semi-coherence. By then, I was too mentally numb to fully appreciate the enormity of what had happened on our chase, and to the OKC community.

    We had heard intermittent radio reports of damage and possible casualties in Moore throughout our time with the second supercell; but as we headed back through Oklahoma City toward Norman, those reports grew ever more grim. There were stories of entire subdivisions levelled, houses scoured from the foundations, and body parts found. As storm observers, we must not feel guilty for merely watching them; and we have no control over what they do and where they go. But we must always keep the victim's circumstances in mind. On this night, it was becoming apparent there would be many thousands of them -- over 40 of whom would never again see the light of day, and over 600 more who were physically injured.

    In days to come, there would be stories of courage and carnage: heroic rescues and gruesome discoveries. A man gathered many of his neighbors into his underground storm cellar before it hit, almost certainly saving some of their lives. Tornado victims able to stand -- some bloodied and battered themselves -- cared for the badly maimed and helped to keep them alive until medics arrived. Emergency rescue personnel and disaster relief workers (from churches, Red Cross, etc.) poured into the area within hours and remained for days, saving lives and offering immediate, much-needed aid. Perhaps the most horrible story among many: One woman stuffed her 11 year old boy into a notch under a bridge along I-44; but with no such space for herself, she held her boy's hand as the tornado engulfed the overpass. As she was losing her grip on the bridge, she told her boy "good-bye" and "I love you;" then let go of his hand as she was blown away to her death.

    Out of this disaster could come very good things, however, for example: reinforced safe rooms in new homes, greater public awareness and appreciation of severe weather hazards, and scientific discoveries about tornadoes based on the huge volumes of data and images gathered out in the field. This event also teaches important lessons about the science, safety and public policy of severe weather. It is important for those affected by the disaster to know that, in many ways, their deep suffering will not be forgotten and will not be in vain.

  • Chickasha tornado emerges as a dominant cone vortex

    Menacing "mothership" storm base with swollen Chickasha tornado centered firmly beneath

    Satellite tornado appears to right (NE) of Chickasha tornado

    Satellite tornado emerges to left (W) of Chickasha tornado

    Chaser jam in Chickasha behind violently rotating, pre-Bridge Creek wall cloud

    "Wedge" tornado about to do F5 damage in Bridge Creek

    Ft. Cobb tornado under Storm B, as seen from 38 miles away

    Brief, diffuse, multivortex Lake Chickasha tornado (Storm B)

    Violently rotating wall cloud cuts clear slot just prior to Dutton tornado

    Dutton tornado (Storm B) in an early conical stage

    Deep zoom of Dutton tornado with multiple vortices

    Dutton tornado grows quite large, wall cloud develops inflow tail

    Minco tornado early, as a bent cylinder

    Minco tornado widens with large subvortices

    Anticyclonic flanking-line tornado 15-20 seconds after unroofing a house

    Violent Mulhall tornado still enlarging SW of Abell

    Wide-angle of 1/2 mile wide Mulhall tornado under 10 mile wide updraft base SW of Abell

    Power flash within violent Mulhall tornado, now nearly 1.5 miles wide between Abell and Mulhall



    Related Links

    My personal Editorial Comments from this tornado event (from 2002)

    Formal research paper on the outbreak by Thompson & Edwards (Dec. 2000 Weather and Forecasting)

    Formal research paper on the outbreak by Edwards et al. (June 2002 Weather and Forecasting)

    Satellite images and loops from Scott Bachmeier

    Outstanding radar images of the supercells from NWS OUN

    Large radar-image set from Travis Smith

    Was Storm A initiated by a horizontal convective roll?

    NOAA Service Assessment in PDF format.

    [The synoptic overview and weather map are grossly oversimplified and erroneous; but several of the recommendations (e.g., unsafe shelter under bridges) are right on target.]

    V.O.R.T.EX.-99 field messages during the outbreak

    Storm Prediction Center

    Norman NWS Event Page

    Roger Edwards Home Page

    Rich Thompson Home Page

    SkyPix weather photo gallery

    More information may be added as it becomes available.