Bennington Kansas EF-4 Tornado May 28th 2013

Jul 21, 2013

Summary:

Intercepted stationary supercell which went on to produce EF-4 tornado that also sat stationary for nearly an hour!

 

 

 

 

Stats:

Tornadoes: 1

Hail: 1.00″ (quarter)

Wind: est 55mph inflow winds.

**NEW CAREER MILESTONE** 6 consecutive chases yielding tornadoes!

The Setup:

Main waves from pervious days system moved on to the east, leaving behind a very warm, moist, and unstable airmass. The big problem with today was lack of shear as the plains sat in between waves. With almost no shear to be found in the plains and the next wave not arriving off the CO foothills till that evening, out west seemed like it might be the best marginal play. There was plenty of instability across the entire area, but no obvious triggers. One potential source for lift came in the form of remaining outflow boundaries from the previous days storms. This boundary would act as a sort of psuedo cold front and *could* trigger a few isolated storms. Directional shear was good, but speed shear was awful. Forecast CAPE values around 4000 and above could potentially offset the bad speed shear though. Without a good forcing mechanism to light off storms, SPC went with modest tornado probabilities across the entire area.

Detailed Account:

We awoke today not in the most positive of moods. Today appeared to be an iffy chase day when pouring over the models in the morning. In fact, my facebook post that morning stated “today might be the day that breaks the tornado streak.” Fortunately for us, we were already out there and it would be foolish to completely ignore the day, afterall there WAS potential, it was just going to be difficult to pick out the best area in such a wide, marginal target area. We chose to play central Kansas, since we were already nearby, and the area looked to be the target area for the following days chase. The presence of outflow boundaries also gave us a hint that today could yield a surprise. We left our hotel in Hays and congregated at I-hop where I finally got to meet chasers Scott McPartland and Dave Lewison. Two chasers from New York with whom I have great respect for, and have been chatting with for years without having actually met. It was nice to finally shake their hands.

They too shared similar thoughts on the day, we were all feeling somewhat lazy about the day. Sort of an “Eh, we’re already here so might as well.” We ate our breakfast and then began our slow treck south and east. The visible satelite was our guide, the outflow boundaries were slowly pushing the cumulus south and east away from us, so we just kept pace. As we neared the Salina area a massive storm blew up far away near Concordia, KS with excellent radar presentation along with multiple reports of large tornadoes that were barely moving. I wasn’t too upset knowing it was nowhere near our target area and that there was nothing we could do about it. It did, however, let me know that if a storm could pop near us, it would be in a similar environment and could do the same thing.

As we sat just north of Solomon, KS (east of Salina) it started. A storm rapidly developed near the boundary. Excitement quickly grew jsut as fast as the storm did.

This part of Kansas is a little tricky to chase. The roads are gridded, but awfully maintained and some of the muddiest when wet. The terrain is also pretty hilly in this area compared to the rest of the state.  We didn’t have to go far to get a view of the base, and decided to pull over when we had a good view. The storm, in its infancy displayed pretty dramatic supercell structure with a barber poll updraft and dramatic mammatus that stretched overhead and down the eastern horizon. For a storm barely 30 minutes old, this was impressive.

I realized the storm wasn’t really moving and it was time to move in for a closer look. While repositioning on one of the awful backroads, I encountered a sudden canyon in the road with no time to stop or turn to avoid it. The vehicle violently bottomed out with an awful noise and right away I was concerned about something being broken or damaged, luckily the vehicle seemed to come out un-scathed and we were able to keep on going, but talk about a moment of fear.

As we neared the town of Bennington, the supercell began maturing and a funnel soon dipped down. We were unable to confirm a ground touchdown due to the tree line blocking our view, but I have seen numerous funnels like this make it down. It would not surprise me at all to learn it did. The funnel lasted about 90 seconds and then roped out as I kept us on the move to get closer to the base.

After passing through town we moved south and then west to the intersection of highway 81. Infront of us was what can be described as the most rapidly rotating wall cloud I have ever seen. The inflow into the supercell was incredible and we knew something big was trying to develop. We found a shoulder to pull off onto and setup our tripods to await the coming show. The inflow began sucking napkins out of my truck and I had to roll up the windows. The wall cloud began spinning faster and faster and after a couple minutes I was dumbfounded that a tornado had not touched down.

Finally, an RFD surged made the entire circulation tighten up and the tornado touched down.

The tornado started as a cone funnel with multile suction vortices under it.

The tornado quickly grew into a very large cone, and to our amazement, sat nearly stationary for nearly 20 minutes as we watched it from that spot as it wobbled from side to side. The next series of images are video stills from this event.

Eventually the tornado became wrapped in rain and we decided to re-position.

I thought at the time the tornado was moving towards us, and we re-positioned about a mile east of it only to look back and realize the tornado still had not moved. In my years of chasing I have gotten used to constantly needing to move to stay ahead of the tornadoes, but with this one being stationary it became apparent the usual tactics would not work, and we now had to backtrack. Knowing the tornado became wrapped in rain the game was simply trying to find a view of it again. Sometimes going further north can offer a view when dealing with highly rain wrapped tornadoes, so thats what I chose to do.

We regained our view, though it was somewhat low contrast but we could see the tornado had morphed into a partially rain wrapped wedge.

We stopped at this location to watch the tornado again since we had a view. We kept wanting to assume the tornado was eventually coming towards us, and we were ready to reposition quickly if it did so, but it just sat where it was.

The tornado briefly transitioned to a stovepipe, before wedging out again and becoming wrapped in rain.

We lost view of the tornado again in the rain and at this point we decided to move back through the town of Bennington, as our option north curled into the core and no real backroads to mess with.  The structure on the supercell was amazing at this point so we opted for a few shots. I had a moment of terror when my camcorder started flashing a hard drive error, to think I could have potentially lost the video I just took was heartbreaking and I wanted to throw up. I immediately plugged in my camera, and luckily for the first time ever I had decided to take my 2 terabyte external hard drive with me on a chase. I hooked it up and was able to dump the footage onto it before something potentially worse happened. Crisis averted.

Back on the storm, the supercell STILL hadn’t moved. I have never been on a storm like this before and I almost didn’t know what to do. We went back and forth several times thinking we had to stay ahead of it, only to turn around and see the storm hadn’t moved. It was silly in a way, but definitely something new for me to learn and experience. After about 90 minutes other storms started going up around our supercell and it appeared a messy complex was about to take over. We moved south one last time to get a final view. There, while doing a 3 point turn I backed down an embankment that was steeper than it had looked and we  almost got stuck, but luckily I was able to switch on the 4 wheel drive and crawl out. Another crisis averted.

Knowing the now linear storms would eventually lose the  instability that fueled them we called the chase, booked a room in Salina and met up with several other chasers where we had a well earned celebratory dinner and roomed up for the night.

Video:

Conclusion:

The Bennington EF-4 is easily a top 5, career tornado for me. The fact it was so large and sat nearly stationary for so long was something I never experienced before. Our position early on allowed me to capture a solid 20 minutes of tripoded video of this amazing tornado. 2013 has certainly become the year of quality over quantity.

A couple big lessons learned on this day, with the first being how different your chase strategy needs to be when dealing with a stationary storm, the second being the forecast. This was a fairly marginal setup that was lacking any shear. It just goes to show what strong instability and a boundary can do.

Radar Images: 

Map: Arrow shows location of our main tornado viewing position.

SPC Storm Reports:

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