July 14th had it all. Boundary, great moisture, instability and good low level shear. We blasted from Pierre, SD to central Iowa as storms formed and became severe and tornado warned. Several tornadoes did occur in central and eastern Iowa with one particular tornado we just missed by 15 minutes being the most intense near Lake City. Frustrating day to say the least, but we still managed some great supercells and a tornado late in the day. Moral of the story is to NEVER give up until storms are weakening and loss of heating reduce instability.
June 20th featured extreme instability, moderate wind shear and good lift along an advancing boundary over Iowa. We started the day from Denver, CO as it was the first day of the tour. After an early departure, we made it just east/southeast of Des Moines, Iowa (650 miles later!) just in time for storms to explode. The first supercell we intercepted was just east of Des Moines and never had the “look” like it wanted to become tornadic. Nice structure and a rotating wall cloud occurred, but it could never tighten up enough to produce a tornado. We dropped south and headed back west a little bit as a second storm quickly became organized. It developed a strong hook echo on radar to the west of Pella. As we arrived in town near the factory, we stopped to watch. Intense lightning was also occurring, a tell tale sign of storm intensification. Within a few minutes, a large bowl shaped funnel formed. Soon it developed into a full fledged cone shaped tornado that was on the ground for several minutes. In my haste to shoot video, time lapse and digital images, I failed to get a proper focus on my camera and thus most images were slightly blurry. The tornado dissipated and the storm eventually weakened as it moved east, ending our chase. A great first day for Tour 8!! Enjoy the pics, blurriness and all !!!!!
June 28th held good promise for supercell storms and potentially tornadic ones to boot. Great moisture, instability and wind shear were forecast across southwest through northeast Iowa. A composite warm front/outflow boundary existed along that corridor and would be to focal point for several tornadic supercells. We were in the Des Moines area and drifted southwest towards Winterset. Soon a cluster of updrafts rapidly formed at the triple point south of Nebraska City, Nebraska. One dominant storm emerged from them. As we blasted west, then south towards Bedford, Iowa (our target!) a tornadic storm developed southwest of Corning, or about 25 miles north of the Bedford target. Since this storm was insanely electrified, had a large wall cloud and great structure, we couldn’t leave it to drop to Bedford for the approaching tornadic storm west of town. It became tornado warned, like the Bedford storm did as well. We stayed with it and watched several tornadoes form and the storm cycle numerous times. We thought it would produce a significant tornado a few times. Most were short lived and sometimes hard to view. Still, a very successful day, 4 tornadoes later, and a pretty supercell. There were over a dozen tornadoes in Iowa this day and a couple were very pretty. Late June and July in Iowa can sometimes be magical!
October 4th looked crazy on paper. Great shear, super lift, great instability and moisture for Oct spelled big trouble for the folks in eastern Nebraska and western Iowa. We left early morning in heavy snow and fog from our home in Colorado, and headed towards Lincoln, NE where we’d decide to head north or east. A supercell formed north of Columbus and was moving away from us so we decided to play the patience game for something further east. Soon a wedge tornado formed from the first supercell and we were feeling pretty bummed. Finally our storm got going as it crossed into western Iowa, dropping a large tornado west of Sloan. After an occlusion, a second, third and fourth tornado formed and the latter becoming a large 1.5 mile wide wedge heading near Climbing Hill northeast towards Cherokee. We had to stop the trip as we encountered a destroyed farmstead north of Climbing Hill, where our search resulted in no injuries, except farm animals. Fortunately, no fatalaties occurred that day, but a lot of destruction of property. Here’s a 10 minute video from this day:
April 9th took us to the warm front in western/northwestern Iowa. A supercell developed on the southern flank of a cluster of storms, and became the storm of the day. Very good shear, moisture and instability would allow this beast to spin for hours! We witnessed 12 tornadoes from this monster, with many strong tornadoes occurring after dark. Photography is tricky when you don’t get a ton of lightning, thus a few of the images are a bit blurring caused by long exposures at high ISO.
July 19th was a day I thought we would be in Canada. A strong trough, with good moisture and instability tracked along the US and Canada border. A boundary had formed from northwest North Dakota into western Iowa and would be the focal point for severe storms. We intercepted a supercell near Williston, North Dakota and tracked it well south of Bismark, North Dakota, over a 10 hour chase! It was either severe or tornado warned the entire time. What a beautiful storm. It arguably was the prettiest supercell of the year. It produced dozens of severe hail reports including hail baseball sized.
June 11th was highly advertised as a big tornado potential day. Shortwave energy was ejecting from the high plains and would interact with a boundary from northern Kansas through Iowa and Minnesota. By the end of the day, several fatal tornadoes would occur, with the most noted being the Little Sioux, Iowa tornado and the Manhattan, Kansas tornado. We chased in Iowa this day and intercepted several storms that had tornado warnings, including the Little Sioux storm, which was quite messy and rain clogged.
June 6 was a day that had decent supercell potential, but we underestimated the tornado potential farther north. Several tornadoes touched down in Wisconsin, which was too far for us to get to. We played the outflow boundary/front intersection over eastern Iowa. By mid afternoon, a supercell developed near Iowa City that became tornado warned for 2 hours, followed by 2 more supercells farther south in Washington county and finally Ottumwa that were beautifully structured. The corkscrew supercell above was near Ottumwa and was tornado warned, and rightfully so! In the end, the low level flow was just too weak to produce an significant tornadic activity.
This day took me to Iowa for high based supercells. The set up wasn’t ideal with only low to mid 50’s dewpoints with temps in the mid 80’s. By mid afternoon convergence along a west/east oriented boundary would be the focal point for severe thunderstorms where moisture pooled along the boundary. Storms fired in Green county and back built and moved southeast into Dallas county. This storm produced 2″ diameter hail and had decent structure. During its first cycle, it produced a weak tornado for about 1 minute. Later when it went HP, it had a very nice rotating wall cloud. Finally it lined out around 9:30 PM and moved south of Des Moines.
This page contains several more photos of tornadoes and storm structure from the Waterloo/Blackhawk county, Iowa tornadic supercell of May 11, 2000. After extensive review of my video, I have confirmed 7 tornadoes from this supercell. Images of all 7 tornadoes are contained on my Iowa pages. So, please check out all the pages, and enjoy!