April 22nd 2011 St Louis Airport Tornado

Feb 26, 2012
St Louis…
Summary:
Intercepted tornadic storm west of St Louis by core punching to get into the hook. Pursued storm on typical horrible MO backroads noting large hail laying on the ground. Was about to call off chase when storm ramped up and began producing tornadoes as it entered the metro area including an EF-4 tornado only a mile south of us as we stay north of it and watch powerflashes on I-270 as tree debris rains down from the sky. Overall a crazy chase!
Stats:
Tornadoes: 1?
Hail. 2.50″ [tennis ball]
Wind: est 60mph inflow to tornado as tree debris falls from sky.
Miles: 640
First: Live stream shown on local news station.
Detailed Account:
I wasn’t even sure I wanted to chase today. The setup did hold some potential for tornadoes though it was apparent the best spot would be in bad terrain. With gas prices through the roof I was not feeling a marginal day in the jungle but Matthew Cumberland and Jonathan Williamson were willing to team up. We chased in Matt’s vehicle which is smaller than mine and thus better with gas so split between the 3 of us it was a rather inexpensive chase. We left Chicago around 1130am just as SPC upgraded the day to a moderate risk. On our way down we drove through some of the areas that were hit with tornadoes on the 19th, quite a bit of damage remained along the highway that I was not able to see at night when we were actually there.
As we entered St Louis initiation began further west than we were hoping [I hate when that happens] so we went into chase mode without any real time to stop. The storm began to organize on radar and our limited road options gave us 2 options. It was either core punch to get into the hook or turn south sooner and let the storm come to us. Naturally I opted for the first option. We were able to make good time catching the storm and the core punch brought on some hail up to quarter size.
Radar image during the core punch, our location is the tan dot/circle.
We came through and got our first look at the inflow region of the storm which showed some elongated shelf like structure and no real rotation.
Before this the storm was much more organized with a big wall cloud, fortunately it didn’t produce while we were far away otherwise we would have missed it. We did not have much time to stop and watch the storm as the RFD region quickly moved over us.
Road options to pursue the storm east were limited to windy backroads that meandered through the hills or going even further south to hit the next highway. We took our chances on the backroads for awhile since it kept us closer to the area of interest. Typical Missouri roads and terrain.
We fell a little behind meandering through the jungle but eventually linked up with the only east-west highway in the area. Luckily the storm was paralleling it to the north. The road was located in a valley that had a decent view to the south and east, but to the north was nothing but cliffs, bluffs and trees. We had a decent view of the back side of the storm so as long as it didn’t wrap itself in rain we could at least see.

There were some real obvious attempts at rotation and even a few scuddy funnels as the storm tried to wrap up. Surface flow was a little weak though and I am guessing this was a major factor in the storm not being able to fully get the job done at this point. We watched several failed attemps as the RFD would simply overtake the rotation trying to develop. The storm was beginning to lose its good appearance both visually and on radar. We followed it as best we could until our lovely highway made a sharp turn to the south and would no longer keep us where we needed to be. We meandered back to I-70 on more backroads as our only option now was to hopefully punch through it again on the interstate. On the way we clipped the core with more hail, and at one point noticed some pretty nice sized stones laying on the ground so we stopped to collect a few samples.
Once we made it back to 70 we were ready to call the chase. I was even beginning to get phone calls from other chasers about meeting up for dinner. At that time a couplet rapidly developed on radar and the chase was still on. An outflow boundary we had been eyeing near St Louis [which is where we were hoping storms would form initially] was now interacting with the storm, and it was about to go nuts.
Tornado reports started coming in as well as significant damage reports as the tornado began to enter the St Louis metro area. Given our location behind the storm and where it was heading I did not want to try and drive south but rather stay north of the circulation and punch through on the back side, a maneuver I dubbed “hook slicing.” Other chasers much farther ahead of us were able to get into the notch before the rotation was over the South highway and could not see anything. The tornado was rain wrapped. As we made our approach and as feared, metro area traffic began to slow us down. It was a pretty chaotic scene. Cars stopping under overpasses, cars crawling along at 5mph rapidly swerving due to panicked and scared drivers. It was a worse case scenario as far as I could tell. We were on I-270 N of the airport and began to notice a series of powerflashes to our south.
The tornado was definitely there, but we could not got an actual visual on it. We were being battered with sideways rain and hail and dodging the crazy traffic. I give mad props to Matts awesome driving during this, he definitely earned my trust as far as driving skills goes. At one point we finally made it through and I pointed to the radar and said “look we are in the hook” and as soon as I said that tree debris began slamming the vehicle from the north. It was due to inflow from the powerful tornado that was probably only a mile or 2 to our south. It was moving due east and I was never worried about our location, but try as we did we still could never get an actual visual of the tornado itself. Just powerflashes and falling debris to mark its presence.
We eventually made it into Illinois where the storm finally lined out and the real tornado threat was over. We pondered going back into St Louis to help out and document damage but by now I was hearing reports of all interstates shut down and major chaos and decided it would be too hard to get into the areas, and we would probably be more of a nuisance than a help at that point. We stopped for dinner and headed home.
Here are some radar images during it all:
As we first enter the backside of the hook.
Close up of the rotation couplet and how close it was at one point. We pondered going south on 64/70 but I deemed it too dangerous to chance driving into the tornado, so we moved north to 270 for safety reasons. A good call as I later learned vehicles took a direct hit on 70 while the tornado remained mostly south of 270.
Detailed look at the intense couplet around the time we were observing powerflashes.
This was the image of us in the hook, just after we got slammed by tree debris on the interstate. Unfortunately that moment was not captured on camera, and the stream archive is broken so I was not able to go back and get that, go figure.
A look at the report I made on Spotter Network of the powerflashes and how they line up with the tornado damage reports from Bridgeton and the airport.
And here is the video for the day. For such a wild and crazy experience the video isn’t too exciting but it sums up the day in a nice way. I was too busy navigating and making sure we didn’t drive into a rain wrapped tornado during the worst of it. Gotta take priority sometimes.

Conclusion:
For a day with low expectations it sure turned out crazy. Driving through a major metro area as a violent tornado was ripping through was a first for me and something I hope I don’t have to experience again. It was pure chaos on the interstate. It was a shame no chaser was ever really able to see the tornado due to it being so rain wrapped, but thats what happens sometimes. It was a well rounded, good chase and fortunately despite the intense tornadoes, noone was killed! As far as counting the tornado I am not sure how I handle it. I am the utmost picky when it comes to counting tornadoes, while I did not actually see it, I knew it was there and pretty much experienced it. For now I will leave it off the official tally. Rain wrapped tornadoes…BAH!
Map, first a zoomed out look, green circle is where we encountered the large hail, red circle is where we were north of the tornado.
Now a detailed look at where the worst damage was in relation to us. Yikes.
SPC Storm reports:
Chase write up from fellow Convective Addiciton member Jesse Risley, includes an excellent synoptic overview! http://convectiveaddiction.com/2011/04/23/04222011-st-louis-area-tornadoes-chase-report/





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