Yesterday afternoon the 22nd a supercell of EPIC proportions produced seven destructive tornadoes along a 7 mile path across north-central South Dakota. Among them, one become a large barrel shaped wedge tornado which crossed to the north of the small town of Bowdle. I tracked this powerhouse storm with my partner Sean Mullins (whose picture of the storm made the front page of the local newspaper) from it’s start as a cluster of billowing cumulus in a clear blue sky straight through until its massive blowout as a long line of lightning & hail-filled storms.

The main tornado near Bowdle crossed the highway on which we had followed the storm just behind us as we raced to stay ahead of the tornado. Once it passed north, we stopped to collect data, video & photos while the violent tornado became stationary & grinded into the earth lofting massive amounts of dirt and debris and actually holding the mess in suspension as it quickly matured into a full-blown wedge! As I shot video of the storm powerful inflow winds at our location accelerated to around 100mph. At this point I actually had to sit down on the pavement to steady myself and shoot the best footage of my life so far!

The storm evolved rapidly, growing wider & narrower, producing intermittently visible suction vortices which surely caused the bulk of the damages, so far preliminarily rated EF3+ with winds of 165 mph and higher. Personally, I’m certain this storm caused solid EF4 damage with winds between 166 to near 200mph! I will provide more information & links once they are available. Needless to say, this was a massive and POWERFUL tornado!

Although no wind speed measurements were taken with the absence of the DOWs & lack of damage in the sparsely populated area, from the NSSL Online Tornado FAQ:

“Suction vortices can add over 100 mph to the ground-relative wind in a tornado circulation.”

So, assuming winds in the larger tornado were around 150 mph–a very rough estimate, for the sake of argument–this means the total tangential (horizontal circulating) wind speeds could possibly have very briefly reached 250 mph! Of course, even with mobile Doppler scans, determining wind speeds in suction vortices is generally impossible due to their small sizes (especially compared to the larger tornado) and extremely short, transient lifespans.

For more pictures, visit my photo gallery.