A Detailed Chase Account of the Saturday, 25 May 1996 Chase near Friona, Texas - by Sam Barricklow Preparing for the Chase Saturday, 25 May 1996, was the first full day of my yearly one week chase vacation. I left work about 3 p.m., made a brief stop at Texas Towers (a Ham radio store) in Plano, Texas then headed northwest on the "highway to heaven", otherwise known as U.S. Highway 287. The new 70 mph speed limit helps, but it is still a long, long drive from Dallas to the caprock and Amarillo. For the past dozen years or so, I have made it a point to meet and chase with two of the most experienced, knowledgeable and colorful storm chasers in the world, Al Moller and Chuck Doswell. Over the years- Al and Chuck have provided me with a tremendous wealth of information about and insight into the complexities of forecasting, storm structure, photography and storm chasing. (We are all three very opinionated and rarely agree, regardless of the topic, which makes the experience that much more enjoyable.) Al and Chuck started their annual three to four week chase vacation on the 24th of May. Al called me at work Friday to say they were scheduled to meet Joe Nick Patoski, who writes for Texas Monthly Magazine, in Amarillo Saturday morning. It was my intention to rendezvous and chase with them again this year. From past experience, I knew that Al and Chuck like to sleep in while waiting for the morning computer progs to generate, for the leftover morning convection to dissipate and to allow the atmosphere to begin destabilizing by heating up a bit. They usually arrive at the nearest NWS office between 10 and 11 a.m. each morning. I am a morning person who cannot easily sleep past 6:00 a.m., regardless of how late I stay up. As a result, I frequently arrive at the NWS by 9:00 a.m. or earlier to analyze the available data before Al and Chuck arrive. When Dave Hoadley is in town, he has often already been to the office when I arrive, determined his target and departed. Occasionally he may still be there, hurriedly grabbing the latest surface map before rushing out the door to his car and down the road. Unfortunately, I didn't see Dave this year. I always enjoy trying to decipher his unique and complicated, but amazingly effective forecasts. There were several chasers already at the office when I arrived. The pattern today looked like the proverbial "no-brainer" forecast. A surface low was in southeastern New Mexico with a sharp dry line extending south. It was forecast to move slowly north-northeastward. A 500 mb short wave was approaching from the west. The best 700/500 mb delta Ts were above and east of the dry line. The vertical wind shear was forecast to be more than adequate for supercells. Rich moist air was in place with more juice flowing in across Texas from the Gulf of Mexico. And, the target area was on the magical cap rock of the Texas Panhandle and eastern New Mexico. Who could ask for anything more? The only negative factors were the relatively cool temperatures and overcast skies that covered most of the central and northern panhandle. Chuck and Al were running a bit late, arriving around 11:30 a.m. A consensus had already developed among the chasers on hand, but Al and Chuck went ahead and did their usual thorough analysis. They work as a team, dividing the analysis chores between them, each concentrating on and analyzing different parameters and levels of the atmosphere. Around noon, award winning video producer and chaser Martin Lisius arrived along with Texas A&M meteorology student Jason Jordan, a fast coming forecaster from the Fort Worth NWSFO. The "take the puppy home" Sales Pitch Before leaving the NWS, I presented Al and Chuck with a new two meter amateur radio that I purchased in Plano, Texas on the way out of Dallas the day before. Al had gotten his amateur radio license a few years ago, but he had never bought a radio. He spent his money on photographic equipment instead. During past chases, I had loaned Al a walkie-talkie, but its limited range made communications difficult unless we were in close proximity. So I decided to try the "take the puppy home and see if you like it" sales technique on them, hoping Al would see the utility of having a real radio and then buy it from me. (It worked!) The Target Clovis, New Mexico was chosen as the target. Clovis was located northeast of the deepening surface low and in sunshine just west of the cloud deck where maximum instabilities might be realized. All favorable factors should peak near or just east of Clovis during the afternoon. The Drive to the Dryline Al, Chuck, Joe Nick, Martin, Jason and I departed at the same time, but in three different vehicles. The new radio allowed Al and Chuck to participate in an extended discussion with me, Martin and others during the drive to Clovis. We commented on the still visible storm damage along the highway southwest of Canyon from last year's June tornadoes, as well as the thick choking smell of manure flowing from the numerous feed lots along the way. (The locals call it the "smell of money".) The sky was solidly overcast. We strained, looking west for breaks in the overcast and glimpses of towering cumulus. The sky's appearance began to change when we passed through Friona for the first time. A few breaks in the overcast appeared with small dark bases visible to the west. At Bovina, the atmosphere began to bubble. Towering cumulus was developing in all quadrants. We continued west toward the dry line and clear skies, expecting more substantial convection to develop further west. At Farwell, on the Texas side of the border, a young CB with a short anvil became visible to the west through scattered low clouds The low clouds were almost totally gone by the time we arrived in Clovis, New Mexico. Selecting the Right Storm There were two problems. First, the most mature of the three or so young CBs developing from southwest through northwest of Clovis was moving into an area with a poor road system. Second, even though the southernmost updraft in the complex to the northwest had a rock hard appearance, something just didn't look right. It was still very multi-cellular, sending up one puff of fairly intense convection after another. And, glaciation seemed to be occurring too early. This storm was still young and had promise, but there were too many negative factors in both its appearance and its location. The Decision to Go Southeast I stopped briefly to chat with Martin, Jason several other chasers at a gas station. Martin said that Gilbert Sebenste was watching The Weather Channel at the Holiday Inn. Gilbert reported that radar showed a storm developing ahead of the dry line southwest of Muleshoe, Texas, southeast of Clovis. Looking in that direction, we could just make out an anvil. Al and Chuck had gone a little further into town to a truck stop to make a "pit stop" for drinks and other refreshment. While proceeding to the truck stop, I passed at least 15 chase vehicles, including Warren Faidley's armada as well as several students (I assume) who were driving sub-compacts. After a brief discussion with Al and Chuck, we decided to go after the storm to the southeast. Al, with his "high contrast" vision could see hints of hard convection under the south end the anvil. Intercepting the Storm We drove southeast on highway 84 past a rain shaft just south of the highway. A rain free base located several miles south of the highway came into view as we skirted the northeast edge of the rain area. We parked by a field just east of the small town of Lariat, near the intersection with farm to market road (FM)1731. At least six and maybe as many as eight chase vehicles stopped within a quarter mile of each other, gathering near the entrances to two freshly plowed fields. Our First Observations and Impressions The storm looked rather benign at first. The rain free base (RFB) was absolutely flat, but the edge of the rain shaft was sharp. A rain foot developed and extended out underneath the RFB. Soon scud formed at the edge of the rain area above the rain foot and rushed underneath and then up into the RFB. A shallow lowering formed briefly. More scud rushed out of the rain area. This scud began to slowly rotate underneath the RFB. It then began to rain on us. My attention to the RFB was broken for several minutes as I jockeyed my scanner, looking for severe weather reports on local public safety channels. The rain tapered off and everyone jumped out of their vehicles to observe, photograph, video and discuss the storm and to formulate our next move. The updraft base to the south had flattened again and resumed its benign appearance. This base apparently represented a "hot spot" at the south end of a multi-cell complex where cells were developing, breaking away and moving northward with the upper level flow. As is so often the case, it was difficult to perceive that a rotating updraft was developing and passing just to our west. Observation of the developing updraft was hindered because of light rain moving overhead and northward. Shortly, it was to become clear that a cell in this multi-cell complex was moving downstream, intensifying and ROTATING. Soon, evidence of intensification could be seen in the form of a developing inflow band. This band appeared as a slightly darker linear feature that extended eastward three or so miles from the RFB along the bottom of an unbroken cloud deck. This feature was initially quite difficult to discern. As a result, the chasers disagreed on its significance. While the discussion ensued, the still relatively small RFB, then located a mile or two to our northwest, developed a somewhat circular appearance. Several shallow, but slightly lowered and curved cloud bands were evident in the small RFB. In addition, lightning frequency increased in and near the intensifying rain area immediately north and northwest of the RFB. The Decision to Chase THIS Storm The discussion intensified. Should we chase this storm or go farther south to clear skies, higher temperatures and better instabilities? The choice was not yet obvious. What to do? I took the blatantly non-scientific approach of pulling a quarter out of my pocket, flipping it and announcing that heads we go north, tails we go south. It was heads! We went north up FM1731. The Chase The chase was on, but by the time a decision was made, the RFB was several miles farther north. We had to recover quickly. Martin and Jason went farther east before turning north and were moving rapidly north on FM214. We maintained radio contact on 146.520 MHz as we pursued the storm along parallel tracks. Just south of the intersection of FM1731 and FM3333 Carson Eads, N5LTN, popped in on the ham radio. Carson reported that he and his team could see a substantial wall cloud. Tim Marshall, Gene Rhoden and Bruce Haynie were with Carson. Michael Cohen, KB5KAR, and Steve, a chaser from the east coast were following Carson in separate vehicles. They were east of the storm driving north on a DIRT road! Steve was driving a compact rental car with low ground clearance. Soon Carson reported that Steve had gotten stuck in deep soft, but dry sand. Mike stopped to help. The chase was over for them. Carson and his crew continued north. We got our next look at the quickly intensifying wall cloud about the time Carson checked in. The RFB was rotating hard with fast upward motion just below and and at cloud base. The RFB had grown from the 1/2 mile diameter when last viewed, to approximately three miles across at this point. The storm had made a rapid transition into the classic supercell category. The First Tornado As we prepared to leave, a small needle shaped funnel quickly appeared. Its weak circulation touched the ground briefly before abruptly dissipating. The first tornado occurred approximately 2 miles east of FM1731, just south of FM3333. Al asked for someone with a cell phone to contact the NWS and report the brief touchdown. A tornado warning was needed for this storm. Al commented that "A pretty major event may be about to happen". My adrenaline started to pump! . We continued north to Bovina and then turned east on highway 86, approaching the western edge of the large rotating RFB and wall cloud. Golf ball-sized and smaller hail littered the road in and east of Bovina. Dense hail fog slowed us momentarily just east of town as we drove under the rear flank downdraft (RFD) clear slot. The bright foreground under the RFD coupled with the dark shadows beneath the RFB still concealed the core of the updraft. Traversing the RFD The cloud motions were wild and chaotic along the RFD/RFB interface. The descending RFD winds tore at the edge of the updraft, ripping off cloud tags and shoving them downward. More wild motions underneath the south end of the RFB and the adjacent flank were coming into view. It was difficult to tell where the rotating RFB/wall cloud ended and the flank began. We were forced to slow to a crawl while the most intense updraft seen so far crossed the highway ahead. Suddenly, the updraft rate accelerated violently approximately 300 to 400 yards east-northeast of my location. The extremely rapid upward motions appeared completely linear at first but, within a few seconds an abrupt and sudden change from linear to circular motion occurred. One might assume that a landspout type vortex stretching process may have been occurring. Rain curtains that appeared to be in the immediate vicinity of this intense updraft along with dust directly underneath at the surface did not exhibit rotation prior to rotation appearing at cloud base. Rotation appeared to begin at cloud base first and then extend to the surface. A shallow circulation could have existed at the surface first, or somewhere between the surface and cloud base, but I saw no evidence of it. Although again weak, the second tornado was observed to touch down briefly approximately 200 yards north of highway 86, approximately six miles east of Bovina in an open field. Driving Deeper into the Shadows Perhaps the most dramatic and risky part of any chase is going from the sunlit area near a storm into the dark shadows underneath the updraft. This is especially true for the more massive classic and HP supercell configurations. As we drove deeper into the shadows under the RFB and flank, a large low and ragged wall cloud slowly emerged from the shadowy darkness approximately three miles to our north. A new RFD slot was developing rapidly, cutting into the RFB immediately south of the monstrous wall cloud. Several thick vertical bands rotated around its edge. The bands extended from the RFB/wall cloud juncture downward, curving in toward its center, almost touching the ground. A flurry of cloud tags (fractus) and scud clouds darted about in different directions underneath the monster as though they were trying to avoid being eaten. The motions at the nose of the RFD slot were spectacular. Bursts of violent updraft developed and sporadically formed short lived funnels as the RFD knifed into the RFB. We were met by an intense shear line along the flank, now directly above FM214. Abrupt changes in wind direction from hard out of the west to hard out of the east shook the chase vehicles. Approximately three miles north of highway 86, we drove under the the nose of the new RFD intrusion as it streamed from west to east over the road, an apparent change of almost 90 degrees from the previous RFD slot. Waves of wind driven "atomized" rain washed over the windshield as we penetrated multiple rain curtains I had to keep both hands tightly on the steering wheel as 50 to 60 mph westerly RFD winds rocked my van. This was quickly becoming a "white knuckle" chase. After passing through the worst winds, I quickly glanced back to the west-southwest and observed that the RFD slot had not turned the corner along the eastern edge of the wall cloud. Instead it continued to flow almost due east and weaken, like a dagger had been thrust into and quickly withdrawn from the RFB. Looking to the west, a new RFD slot was developing. This one had a more northeasterly trajectory. Tornadoes NW of Dimmit As we entered Dimmit, skylight was descending through the new RFD slot that was now overhead as it wrapped around the eastern side of the large wall cloud. Diffuse sunlight illuminated the eastern side of the wall cloud. The wall cloud was on the western edge of town, no more than a mile or two away. At this point, we felt that the intense RFD was undercutting the updraft and new development would likely occur in a more northeasterly direction. Doswell, who was performing the navigational chores, plotted a course from Friona to the northeast on highway 60. Near the center of town, we saw terrified residents and whole families running from their homes to storm cellars, literally clutching babies in their arms as the meso approached. This was a surreal scene and emotionally gut wrenching. It was rewarding to know that we helped warn the citizens of Friona through numerous reports to the NWS. After turning northeast on highway 60, we had traveled only a couple of blocks when Al Moller reported "TORNADO!" over the ham radio. We immediately made a "U" turn and saw a fully developed sinuous tornado just northwest of town. Friona's warning sirens began to wail as I focused the video camera on the tornado. Multiple vortices developed quickly, persisting almost a full minute before dissipating. Curiously, a columnar mass of ill defined clouds began boiling immediately south of the multiple-vortex tornado. Clouds repeatedly formed on the ground and gushed up into this seething amorphous column. I'm not sure what it was, but it persisted for several minutes while moving quickly to the northwest. As we drove north on FM214 from highway 60, a second writhing column formed near the first. Both continued moving to the northwest. Tornadoes? I don't know. They were too distant and poorly defined to tell for sure. Both of these "things" were in contact with the ground. I momentarily lost visual contact with them as we turned west and continued on FM214 at the junction with FM2298. After pondering these anomalies momentarily, my attention again shifted to the larger picture. A new RFD slot was opening. Sunlight shining through the developing RFD slot and reflecting off of the plowed fields and thick haze quickly reduced visibility. More Tornadoes, The Anomaly and a Large Rapidly Rotating Wall Cloud on the Deck Approximately four miles west on FM214, a brief small flanking line tornado formed about one mile south of the road. It lasted only a few seconds. Again the sky to my immediate south and west was full of seemingly unorganized chaotic motions. Just beyond the glare of the developing RFD slot, a low tail cloud came into view. This time, the RFD slot developed from south to north. Moving back under the updraft base and into the "shadows", the two "things" came back into view. Whatever they were, they merged into a single larger entity. It had the appearance of a large tornado, but visibility was too poor for any of us to tell for certain. Just west of the RFD slot a long skinny occluded flank extended south maybe four to five miles to the area where the large unidentified "thing" had last been seen. The southern end of it was eroding quickly. Rotation and updraft were quickly focusing further north. Al, Chuck and Joe Nick drove under the tail cloud to "sample the environment". Within a few seconds, Al again excitedly announced "TORNADO!" over the radio. The tornado was south of the highway, at about the 10 o'clock position at the "new" south end of the occluded flank. The tornado was a little less than a mile south of FM214 moving north, toward the tail cloud and the car with Al, Chuck and Joe Nick inside. I asked Al "Are you going to let it pass east of you?" No answer, but I saw headlights coming toward me rapidly as they made a hasty retreat. The tornado maintained full contact with the ground for about 30 seconds. The circulation at cloud base rapidly expanded and the whole flank lowered as the tornado lifted. The tornado was small and had been at most 100 yards wide, but the expanding parent circulation had now grown to at least 300 yards wide and lowered to within a few hundred feet of the surface. The rapidly rotating updraft crossed the highway about 1/4 mile down the road in front of me. Numerous cloud tags (and occasional tornadic winds) danced along the ground just north of FM214. Doswell commented on the radio that it appeared the process of vortex breakdown might be occurring on the scale of the mesocyclone, inhibiting the concentration of the vorticity and a significant tornado. While I videoed this event simultaneously with two video cameras, Amarillo's Doppler Dave and his TV crew set up operation next to my van and transmitted a live report. He predicted that a tornado was imminent. I guess they had not seen the previous tornadoes. We decided to go farther north to get ahead of the storm in a better position for the next tornado. We drove east on FM214, then north on FM1057, past the slow moving in operation Doppler On Wheels (DOW). A new wall cloud was developing just north of the intersection where FM1057 turns east. The old meso was still intact and several miles to the west-southwest. Two mesos, one storm. We continued east on FM1057, then turned north on highway 385, then west again on FM214. Approximately six miles west of highway 385 on FM214 Al again announces "TORNADO!". A tornado came into view though partially obscured the rain curtains of a fully occluded flank about seven miles to our NW . We watched for several minutes as it roped out and dissipated. Since we lost visual contact with the storm for several minutes, it was not clear whether this tornado was produced by the "old" or the "new" meso. Maybe Gilbert Sebenste can shed light on this. A home located about three miles east of the triple intersection of FM214 sustained considerable roof damage from this tornado. (This intersection is labeled as SIMMS in the latest revised edition of the Roads of Texas.) We chased the storm several miles north of Vega before breaking off and turning south toward Lubbock. We caught occasional glimpses of lowerings imbedded in the rain area, but by this time visibilities were poor and rain was falling a good distance away from the storm's main core. This was a very exciting chase, but somewhat disappointing because when we were close, only brief small tornadoes occurred. While clearly visible on video, the images are low contrast. We had only a distant view of the last few minutes of what was probably the most picturesque and photogenic tornado produced by the storm. However, the video of the wall cloud south of Friona is spectacular as is the close up video of the low turbulent wall cloud northwest of Friona on FM214. This chase only whetted my appetite.