Infrasonic Acoustics And Pressure Measured During The 31 May, 2013 El Reno Tornado

[Lanny Dean]

I have finally completed the 4th light revision of the "Infrasonic Acoustics Measured During The 5 May 2013
El Reno Tornado". I do have a few grammar errors that I will take care of before resubmitting it. I have attached it in PDF form so hopefully it can be seen clearly.

This has been a very long road for me...and one that I have kept somewhat mum about. While just a handful of folks know the inner workings of what we were trying to do and why - many do not know (simply by choice and because of an issue with funding about to cease from Nat Geo on his end) I had the great fortune to work together lightly with Tim Samaras in late 2012 and into 2013 on some acoustic/infrasonic stuff I had been working on for years. My funding obviously came directly from my tours, as Nat Geo was rapidly closing the doors on his so to speak. Without going into real detail, $40,000 was to last all year for him and there would be no more for the 2014 season. I had known Tim since 1992 and some may remember when Nat Geo kinda threw Tim, Randy, Sean and myself in a little tornado documentary that would ultimately lead into Storm Chasers and then Tornado Hunters for Randy and I.

Obviously Tim and I kept in contact through the years and ultimately it was my acoustic data that I documented during the 4/14/2012 Conway Springs/ICT tornado event that lead us to the start of the 2013 season. Some of this info was released in the Nat Geo article and tribute after his passing, which I am sure many have already read. And some of you know what kind of a real beating I took from some after his passing, so I shut the tours down and I spent the next 7 months under a rock basically lost and mum. But all things happen for a reason (whatever that might be, I have no idea) and as bad as I hate to say it, El Reno was a success in many ways. We are now more safety minded than ever - and to some degree we have found that we are not invincible. At least some of us have. Due to requests of the family, I had to omit some stuff from the paper but I know some of you "in the know" had been wanting to know where I was and an update. I am still working on it and I thought I would share it. Hopefully this is the correct location. If there are issues with the PDF uploading please let me know and I can email or maybe the staff can help me.

-LFD

 

[rdale]

Neat stuff Lanny. Is this still an active experiment? Do you have audio from supercells that didn't produce a tornado?

 

[Lanny Dean]

@rdale Indeed it is still ongoing. In fact, the latest documentation was the Sand Springs, OK supercell and tornado. As it stands, I have 21 complete data sets - 13 tornadic supercells and 8 non-tornadic (Null cases) Interestingly enough, all 21 data sets produced an acoustic infrasonic signature, however those that produced tornadoes ultimately produced either two or more signatures such as the case with the El Reno tornado, which produced as many as 12-13 independent signatures at any given time. What I have referred to as a TSF (tornado signature frequency). I might add that during the 4/14/12 Conway Springs, KS tornado, Chad Berryhill and I documented numerous signatures between Conway and ICT proper (6 to be exact)

The "null" cases listed above were classified as a legit supercell that produced a "single" acoustic signature over time and space, and that did not produce a tornado. What I have referred to as the SSF (supercell signature Frequency) in the attached paper.

I continue the work with funding coming directly from my tour business - during the tours, and have made some engineering and electronics changes with the hopes to clarify the documentation process a little more during this season.

If you are not familiar with infrasonics, I would highly encourage to start with the work of Dr. Al Bedard. He heads up NOAAs Infrasonic department and Tim introduced me to him back in 2005. A very wonderful guy!