Chase Day: July 21, 1993
The following is a storm-chase account written in the autumn of 1993 for Storm Track Magazine. Slightly different versions were published in the American Weather Observer and TESSA's Weather Bulletin.
Late last May I had the opportunity to read many of the early issues of Storm Track. My friend and fellow chaser, Charles Bustamante, had packed nearly a dozen volumes of Storm Track for our latest excursion to the Plains. Near Glendale, Nevada, I recall reading a fantasy article/cartoon by David Hoadley. The star in this "Gentleman's Chase" wakes up somewhere in tornado alley, has a leisurely lunch, watches a storm develop nearby, and photographs a tornado while in perfect position after a brief drive. For him, it was just another typical chase day.
Charlie and I were making the long and arduous drive home to Los Angeles at the time. We had chased for five days and had seen--maybe a gustnado, maybe a funnel cloud--but certainly no classic tornado. It was my fifth return trip from the Plains in three years, and I was batting way under my weight, tornadically speaking. I laughed to myself while becoming quite envious of Hoadley's fictitious character. How dare this individual reap nature's reward without suffering hours, weeks, and years of frustration! As I strained to stay out of the Nevada sun, I wondered when my chase efforts would pay off. It did not look like 1993 would be the year. It certainly was not likely to be the way of this "Gentleman's Chase!"
Charlie and I were on the road again--in mid-July! We had the opportunity to stretch a weekend into five or six days, so we threw the cameras into the Pathfinder and trucked through that great Great Basin through to the plains of Colorado. Ahhh, Eastern Colorado!--upslope flow, great CBs, fabulous shear, big hail! Awesome storm photography! Tornadoes? Well, a debris-whirl here, a landspout there, here a funnel, there a funnel... Well, Colorado tornados are weak.
Four days of successful severe-storm chasing and photography behind us, we awoke in Colorado Springs and debated whether to head home or to stay and chase one more day. We definitely did not want to make that dreaded drive home much longer than it already was, i.e., by ending up well into Kansas or Nebraska at the end of the day (it was Wednesday, July 21, 1993). Jim Maxwell, NWS forecaster in Colorado Springs, informed us late that morning that extreme northeastern Colorado could go severe that afternoon. We could deal with that!
Several severe weather parameters were forecast to combine from Eastern Montana to Northeast Colorado. Surface low pressure along the front range was drawing moist, low-level air from the east and southeast into Northeast Colorado. A dryline situation, Colorado style, was to develop, as warm, low-level air pushed eastward off of the front range that afternoon. In addition, a warm front, slicing across the corner of Northeast Colorado, would aid moisture convergence from about Sterling to Akron, according to Mr. Maxwell. Upper-level winds from the southwest were to increase that afternoon over the region as a jet streak/vort max moved over Colorado. This would enhance lift and encourage rotation of any storm activity over Eastern Colorado. Also, forecast upper-level diffluence and lifted indices (near -10) were excellent. All of these parameters were courtesy of an unseasonably strong and persistent upper-level trough over the Great Basin. It's a good thing that clouds don't know what month it is!
Charlie and I had a leisurely lunch in Colorado Springs and drove north towards Denver, with the option (very much in the backs of our minds) of jumping onto Interstate 70 and heading home to California should nothing significant develop. Denver was hot and dry at 1PM: 91 degrees, 14% relative humidity, and light winds. At 1:30PM MDT Denver NOAA Weather Radio issued a statement concerning a small shower which we could see to our east, near Deer Trail. I thought that those clouds hardly warranted a statement, but chasing is in our blood and we headed east! This would definitely be our final chase, our last chance for something special in 1993.
The cell was caught around 2PM MDT, near Byers. We visited a grocery store in Byers, just southwest of this small and isolated thundershower. I called my weather office back home for the latest update. (I am the climatologist for Continental Weather Services, Inc., in Encino, California.) A mesoscale discussion for the region had just been issued by Air Global Weather Central at Offutt AFB in Omaha, Nebraska (acting in backup capacity for the National Severe Storms Forecast Center): "Moisture convergence increasing in Eastern Wyoming and Northeast Colorado as low-level winds back and increase in response to approach of a jet streak over Western Colorado. Surface-based lifting index between negative 8 and negative 11 from Eastern Wyoming/Western Nebraska southward into extreme Northeastern Colorado. Weather Watch expected to be required within the next hour or so as energy from the approaching shortwave increases UVV (upper vertical velocity) fields over upslope area." By 3PM MDT a tornado watch box had been issued for much of Eastern Wyoming and adjacent South Dakota and the Nebraska panhandle. Charlie and I were not interested in driving any farther north or east than was necessary. We had a nice little thundershower to watch, it was easy to follow, and it had good potential. It was isolated and moving into an environment more favorable for strengthening.
Still at Byers we visited with a team from NCAR that was watching the "storm" for a hail study. Shortly thereafter they were told to leave the storm and to head back west to their base. (I never could quite figure the reasoning there!) Our storm, meanwhile, was developing, and we headed east on U.S. 36. From about 3PM to 7PM the cell intensified and plodded ss..ll..oo..ww..ll..yy eastward, just north of U.S. 36 the entire time. Charlie and I were transformed from storm chasers to storm perusers (not pursuers---perusers!). Just east of Byers we sat in the truck, right underneath the storm's updraft base and amidst long cloud-to-ground lightning bolts, relishing each crash of thunder. (Believe me, that is a real treat in itself for us California boys!) We viewed a little landspout which spun up below the southern edge of the updraft base. We drove south a mile or so for a better overall view of the storm. We drove east a few miles down U.S. 36 through dusty outflow winds. Again we went a little south, then back to U.S. 36 and east again to keep up. The updraft base was quite ragged, and the precipitation area to its north was getting darker. About seven miles west of Last Chance I set the camcorder up on the tripod. The base of the storm was getting lower, and a wall cloud was trying to organize. Air Global Weather Central put the Plains of Eastern Colorado under a tornado watch at 4:37PM MDT.
Finally, near Last Chance in southwest Washington County, the storm developed to a point beyond mere mediocrity. From 5 to 7PM the storm drifted from northwest of Last Chance to northeast of Last Chance. Around 6PM several gustnadoes (or, perhaps more precisely, "funnel-less debris-whirl tornadoes") spun up simultaneously beneath a rather ill-defined wall cloud. At the same time, a "clear slot" just northwest of this area marked the storm's rear-flank downdraft. (Also at this time, a fellow riding his bike (from east to west) across the country stopped by to marvel---good timing, dude!) Heavy precipitation fell north and northeast of the updraft, and greenish/aqua-marinish tinges suggested big hail. This was becoming a textbook storm. It was moving into an ever-moister and unstable airmass. It was isolated with a capital I--free to ingest as much juicy surface air to its east and southeast as it deemed necessary. Several other storm chasers converged around Last Chance to see what this storm could do. The National Weather Service in Denver had southwest Washington County under a tornado warning shortly after 5PM MDT.
(The 00Z (6PM MDT) weather map showed the warm front through the corner of Northeast Colorado: from the CO/WY/NE triple-point to Brush to Burlington. This put it about 20 miles east of Last Chance. Limon, southwest of the front, had south-southeast winds at 20 knots and a temp/dew point of 83/44. Goodland, northeast of the front, had a southeast wind at 10 knots and a temp/dew point of 76/68. Akron, Colorado, about 30 miles NNE of Last Chance and just east of the front, had southeast winds at 20 knots and a temp/dew point of 75/64.)
Near 7PM a very-impressive-looking updraft was rotating north of Lindon, and it continued to issue funnel clouds and brief debris-whirl tornados. The sides of this saucer-shaped updraft were fabulously smooth and curved! At 7:20PM several chase teams watched from Roads S and 15, three miles north of Lindon. We had two additional cells to watch by then, a small one to the northwest and a new one to the southwest. The primary cell, drifting off to our northeast, was still a monster, but it was having a lot of difficulty maintaining its wall cloud. Charlie and I noticed that low clouds overhead were streaming towards the activity to our southwest. Though we did not grasp the significance at the time, the storm we had been following for over five hours was now feeding an offspring to its southwest. We were reluctant to abandon our primary cell, so we left the chase party and drove a few more miles north and east. We stopped to look around in light rain near Roads W and 17. Our primary storm was even more disorganized, and that little bell-shaped base to the northwest was fizzling fast, too. Low clouds continued to race towards the cell back towards Last Chance!
Lightning in this new cell became more and more frequent, and its very low base was issuing some very intriguing and constantly changing shapes. Though it was about 15 to 20 miles away, we had a decent view of this base to our southwest: intervening precipitation was light, backlighting was excellent. Finally, it became obvious that we should forsake the dying for this burgeoning tail-end Charlie cell. The time was 7:45PM. We had one hour of daylight left in our storm-chase season. This was our last chance chase.
A large funnel cloud took shape as we covered the five miles back to U.S. 36 (along Road W). When we reached U.S. 36 and headed west, our disbelieving eyes viewed a large funnel all the way to the ground! We turned south again onto Road U (two miles later) in light rain and small hail.
Now we were afforded only occasional views of the tornado along Road U: the updraft base of
the tornadic storm was very low, and the terrain was hilly. Only at each hill crest could we see
what was happening---and each time the thing was larger!--it was wider!--it was a big wedge tornado! Charlie and I were incredulous! This was the farthest thing from our minds! We ARE in Colorado, are we not?
The precipitation ended as we churned southward down Road U. Five miles from U.S. 36, we came upon a road west, Road 7. Road 7 headed straight towards the black, menacing, deadly monster! Anticipation, anxiety, and exhilaration reached new heights for Charlie and me! This was our first real tornado---not just some wimpy landspout or funnel-less dust whirl! I turned right on Road 7. I punched the accelerator again and honked at a farm worker who was working with some equipment by the road. He did not appear to be aware of the impending doom spinning a few miles away.
Which way was the tornado going? Probably towards us. Which way were we going? Definitely towards it! How close, how scared, how daring did we want to be? It took us only one mile to decide. We stopped at Road T. It was 8:00PM. The tornado still appeared to be three or four miles west of us, but it also looked at least one-half mile wide! It was not moving forward very fast, however. I pointed the truck east, left the engine running, and we hastily set up the camera tripods. We both felt that we would not be able to linger very long at this site. We had escape routes only to the north and east (and west???).
The weather where we were was wonderful--the view spectacular! We were alone! (Where are those other chasers?!) Charlie's camera clicked away and I monitored the camcorder as the tornado slowly approached. We had an excellent view---there was NOTHING to obscure this grand vision! Sunlit skies framed the black and ominous wedge. How did we feel? We felt awestruck; we felt blessed. This was not Colorado--this was heaven!
The tornado slowly moved east-southeast and gradually became smaller and more compact. Its right-moving path took it to our southwest--about two miles away--but its base was now less than a quarter-mile wide. At this point Charlie and I became more concerned (safety-speaking) with the dark wall of storm encroaching from the northwest, and the classic supercell rotating directly overhead. Thunder to our north sounded like shotgun blasts--perhaps thunder trapped in a chamber of hail. We were in no-man's land: We were in heaven, surrounded by hell.
An amazing sequence of events was about to transpire as the tornado continued to our southwest. Its base began to dissipate, and for a few moments we could see a multiple-vortex structure. Just when it seemed that total dissipation was near, a needle-thin funnel suddenly formed inside of the larger, largely transparent circulation. This "needle-in-the-funnel" was on the ground and it quickly expanded. The large, squat, wedge tornado had transformed into a tall canister, or, columnar, shape. One-half minute later, the lower portion dissipated again, but once more a narrow funnel cloud quickly redeveloped along the ground. The tornado took the shape of a slender, classic-looking twister, then changed back to a canister shape again. To our south-southwest it stood at an angle in "Tower-of-Pisa-like" formation. It quickly roped out over a dusty field, still south-southwest of us, about ten minutes after we had arrived at the intersection of Roads 7 and T in Washington County. (Was "7" for luck, was "T" for tornado?).
How fortunate could two storm chasers be? We had just captured some of the most incredible and spectacular tornado video ever! We were provided with a large, slow-moving and dynamic tornado from a tranquil, obstruction-haze-and-dust-free viewing site with great backlighting and contrast. What do we do now?
Well, we had to try to stay alive. I thought that we might have to pay for our luck by sacrificing the integrity of the chase vehicle. Fortunately, large hail skirted by just to our north, and just a few golf-ball-sized stones sprinkled our vicinity.
A minute or two after the tornado roped-out, a couple in a truck drove up to us to see what we were up to. He had watched the tornado from a field on his farm; she had seen us from their farmhouse, wondered if we were stuck or something, then glanced west and fled to the basement! Now the tornado was gone, and we went a quarter of a mile west to take refuge from the impending wind, rain, and hail at their home. Their home, right on Road 7 and directly east of the tornado's birthplace, was spared because the tornadic storm turned a little to the right.
From the porch of the home of Philip Scott I videotaped the storm as it swirled a few miles to our east-southeast. The base was incredibly low, and the land below it appeared to be awash in hail.
Another large tornado developed beneath this airborne maelstrom as darkness fell, and we did not see it. Little did we care. Charlie and I had just completed the chase of our lives. Our last chance chase had become The Last Chance Chase; our Last Chance chase was a Gentleman's chase, an E-ticket chase from heaven.
Notes of interest concerning the tornados: These tornados of July 21, 1993 are locally referred to as the "Lindon tornados." They are among the largest ever witnessed and photographed in Colorado. The first tornado, the one Charlie and I videotaped, was rated F0 because no structural damage occurred. It injured some animals and tore up some fences, but otherwise hit nothing! The second tornado wrecked a farmhouse and was rated F3. There were no deaths or injuries. Another out-of-season tornado killed eleven people just east of nearby Thurman, Colorado, on Sunday, August 10, 1924. (I believe that that one still remains Colorado's only killer tornado on record.) The tornado that tore through Limon, Colorado, in 1990 was on June 6. Tornado season in Eastern Colorado is generally considered to be mid-May through June. The jet stream is typically too far north of the state during July and August for storms such as these.
There were perhaps a dozen or so chasers and spotters in and around Last Chance and Lindon that evening watching the storm. Apparently, most did not end up in very good position to view Tornado #1. Dean Cosgrove, a NWS spotter out of Fort Morgan, was in good position and saw the large wedge of Tornado #1 develop from Roads W and 7, three miles east of our site. Dean managed to stay safe, videotape the storm, and keep the Denver NWS up-to-the-second on the status of the storm and tornados. He was on the storm from about 4 p.m. to midnight, when it finally weakened near the Kansas border. Another chaser from Denver, Tim Samaras, watched the large wedge develop just to his north while along Road M. Tim's video of the tornado as it drifted to his east is spectacular, but he was fighting rain, strong winds, and poor contrast as precipitation wrapped around the west side of the tornado. Dave Thede and Dave Solomon caught the end of tornado #1 about eight miles east of where it roped out. From there they had a great view of the second large tornado as dusk fell.
Charlie and I called Channel 4 in Denver from the Scott's farmhouse south of Lindon and met their news van at Byers at 10PM. Our tornado footage was seen on the Denver news within the next 15 minutes, and Charlie and I began our happy trek west along I-70. When we arrived home in Los Angeles the next evening we saw our tornado footage again--on The Weather Channel!--which had been showing clips of the incredible storm all day long.
Photo copyright William T. Reid.