24 August 2006 Summary:

Four other graduate students from UND (Adam Chambers, Ben Hershey, Becky Obrecht, and Feng Zhe) and I departed Grand Forks at approximately 12:30pm. Our initial target was an area of clearing just south of the boundary in EC South Dakota. Having been delayed an hour, we were a bit concerned about making our target in time, but we trudged forward.

We initially stopped for data in Watertown, SD (which was encased in low clouds/fog) and debated our next move. After a bit of deliberation we decided to blow off targeting the boundary where we expected storms to fire… this was too far east (in MN). Instead, we drove west towards Redfield, SD to a) get out of the low clouds and b) target any storms that went up near or ahead of the cold front. Winds in this area were from nearly due east and Tds were more than adequate (upper 60s if I recall) for decent supercells.

Heading west on US 212, we patiently awaited our exit from low clouds. Unfortunately, contrast was quite bad, and it wasn’t until we called a nowcaster that we realized that we in good position to catch the southern storm NE of Pierre, SD. No sooner that we learned of this development, the contrast improved slightly and we could make out some weak mammatus on this storm’s anvil.

Once we reached Redfield, SD we could make out a small flanking line and large rain-free lowered base. We took SD 26 to the SW and worked our way towards the storm. Around 5:35pm we spotted the first tube-like lowering below the wall cloud ~30-40 miles away. While we couldn’t confirm anything from that distance, this appeared to be our first tornado of the day after checking the ground survey/SPC reports.

Over the next half hour we worked ourselves down to Miller, SD. Just north of this town, we observed a significant amount of rain curtains around the broad, slowly rotating wall cloud (5:45pm). Near the FFD, a large inflow tail started to form. The storm had a large amount of CG activity; enough that we only ventured outside of the vehicle for very short periods of time.

At 5:55pm, the storm made its next effort to produce a tornado. An additional dense column of precipitation appeared along the southern periphery of the wall cloud along with a bit of a clear slot. Because of our constant movement and lack of continuous video, I was unable to determine whether this precip. was either traditional wrapping rain curtains or a DRC. Shame on me! A small cone shaped funnel appeared, but it quickly dissipated. At this point in time we were nearing Miller, SD. I joked to the others that I wouldn’t be surprised if it dropped a tornado when we entered town. Of course, this is exactly what happened!

We traveled into Miller, SD at 6:00pm. Kinking my neck to look outside the side of the car, I could see another cone shaped funnel form. This time, however, it kept descending. Several local residents slowed traffic to a crawl and we squirmed like worms on a fish hook as we waited to get through town. Finally, we got to the eastern outskirts of town at 6:05pm. By this time, a large cone tornado had developed. The condensation funnel was 80% of the way to the ground, and considering it was over open field and in a wet environment, I’m not surprised there was a lack of debris. After several minutes, the tornado was WSW of us, so we decided to start stair-stepping to the SE again. Over the next 10 minutes, the tornado either a) lifted and descended several times, b) went through varying stages of being rain wrapped or c) continued on the ground with a lack of condensation for brief periods. While the tornado disappeared from our sight at 6:13pm, it reappeared in the form of a narrow snake at 6:15pm. At 6:16pm, the condensation funnel vanished for a second time. The tornado reappeared from the rain curtains as a tilting tube at 6:21pm then quickly dissipated for good at 6:23pm.

By this time, we had gotten ourselves out of position to watch future tornadoes. We traveled east, dropping south at times so we could get a clear picture of this beast of a supercell’s structure (2) (3). We knew what was probably going on several miles to the north in the dark abyss, but we weren’t too keen on traveling north into the rain/dust curtains in hopes of catching a few more tubes.

At 7:18pm, we were approximately 10 miles WSW of Huron, SD. While most of us were still focused on the structure to the north, Adam (who was sitting in the back) noticed a slender rope tornado developing along the back side of the storm. We pulled over and took dozens of pictures of this rope tornado. It danced as if a snake charmer was playing a tune to it. After it developed numerous kinks, it eventually disappeared at 7:24pm. Based on the location of this tornado, it may have been anticyclonic. Due to the diameter of the tornado, the distance, and lack of video/debris, we were unable to tell which way it was rotating. Oh well… Thankfully, I remembered to set the camera to full manual and take a few stills for a panorama before it vanished. The end result is probably my most memorable shot chasing thus far. Adding to the picture is the knowledge that hidden in the frame is a large and violent tornado.

Only ten minutes later, the wedge (2) revealed itself while we were passing due south of Cavour, SD. The scene was strikingly similar to a photo I took from the 29 May 2004 Harper county supercell. We continued to parallel this tornado ~8 miles to its south. We eventually stopped just north of Carthage, SD and filmed the conversion of the wedge into a tall stovepipe and finally a rope.

With darkness quickly approaching, we called off the chase and drove west to get some sunset shots (1) (2 pano) (3 pano). We then traveled to the Aberdeen office and handed over a few locations and tornado times. It wasn’t until 3am that we pulled into Grand Forks tired, yet completely satisfied with tornadic fulfillment.