Thursday, November 10, 2011

Tipton Tornado Rated EF-4 - First In Oklahoma History for November...

Tornado Near Tipton, OK. Photo by Steve Grabman

The National Weather Service (NWS) in Norman, OK has completed its examination of the damage associated with the tornado that struck near Tipton, OK this past Monday (November 7th) and have rated it EF-4 intensity. This is the first time in Oklahoma history that an EF-4 tornado has taken place during the month of November.  An EF-4 tornado produces winds of 166-200 mph.

The "Tipton tornado" was the first of 6 tornadoes produced by a single, supercell thunderstorm that tracked from near the Red River on up North/Northeastward to West of Oklahoma City on Monday night.  The tornado touched down about 4 miles east/northeast of Fargo, TX and lifted about 3 miles Northeast of Tipton, OK, as shown within the red circled area on the image below:

In their report, the NWS states:  "the (EF-4) rating is based primarily on damage observed at the OSU Agronomy Research Station on Highway 5..."  

Below is a photo of all that was left of the research station late Monday afternoon:

That's right...just a vacant concrete slab!

Below is a video of the tornado near Tipton, as captured by  

...and another (very close up) view as captured by (don't try this at home, folks):

The tornado also made a direct (or near direct) hit on the Oklahoma Mesonet automatic weather observing station near Tipton.  Below is a photo of what the equipment looked like after the tornado hit on Monday:

...and below is a graph showing the observed weather conditions as the tornado struck the equipment:

The middle graph (in a generally brown color) shows the barometric pressure at the station.  As you can see, it took a massive dive at the time the tornado struck, registering a minimum of 913 millibars before being destroyed.  The maximum wind gust was recorded at 85 mph, again, right before the equipment was destroyed.  Since the equipment was "compromised" by the tornado, we'll never really know how low the pressure fell nor how high the wind rose, but these are very interesting observations none-the-less (and very rare to be captured in any form).

All in all, a truly remarkable and historic event, even by Oklahoma's severe weather standards!  I'm happy to report that there were no deaths or significant injuries reported in association with this very strong tornado.

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Stu Ostro said...

Good blog, and yes, quite a tornado! One other thing to keep in mind is that the pressure reading was not adjusted to sea level.

Rob In Texas said...


Thanks for the comment! Good point, I've removed the hurricane reference (I didn't realize that the mesonets weren't adjusted to sea level pressure). I'll try and dust off my old formula book when I have some free time later today and see if I can take a stab at the adjustment.

Thanks again!


Shane said...

That damage looks like EF5. "SLAB SWEPT CLEAN." Maybe it wasn't built well enough for an EF5 rating. Still an EF4 is remarkable for Oklahoma during the month of November.

Rob In Texas said...


You're correct, the foundation being wiped clean is only a part of what factors into an EF-5 rating.

I searched the internet for nearly an hour on the evening that I made the original post, and believe it or not I couldn't find a single picture or video of what this building looked like before the tornado...not even on OSU's own website pertaining to their agronomy research program!

I can make an assumption, based on what I've seen of these types of structures in other programs, that it was probably a metal structure on a wood frame. Other considerations would be how the structure was anchored to the foundation, etc.

Thanks for your comment!

Damian Campbell said...

Nice Article..that's all I want to say..Keep it up chap!