Strongest tornado of 2010

[Bob Hartig]

The idea that all tornadoes are multi-vortex is one that has fascinated me for a while. I think it was a video of the Elie, Manitoba, tornado that first got me thinking about it. During the ropeout, you can see the tornado appear to actually unwind like braids in a rope, as if someone were separating all the strands--this in what was by no means a large tornado, but a very compact drillpress. I've since seen this braided appearance in other videos of smaller tornadoes that were transparent enough to reveal their innards, and it has made me wonder just how deep multi-vorticity goes, how many vortices-within-vortices there actually are in the process we call a tornado.

The tornado that followed the Bowdle wedge gave me my first good firsthand look at that possibility. As it morphed from a classic funnel to a truncated cone, I could see a host of delicate condensation threads--I think of them as vortex strands--circulating around its periphery. Looking closely at one of my photos, I can even make out what appear to be smaller strands intertwined within some of the larger ones.

NOTE: At this point I was going to attach a photo so you could see what I'm talking about, but true to form, non-technoid me screwed up the process and my photo along with it. I can't waste more time right now correcting my mistake, but I'll post the photo once I've retrieved it from my card. (Really. I promise this isn't a version of, "I've got a great photo of Bigfoot for you here, and...ooops!") Plenty of other chasers have captured that tornado, though, and the phase of it that I've described, so maybe someone else can post a photo in the meantime.

 

[Wes Carter]

Jeff and Matthew's discussion and Shane's references to multi-vortex tornadoes and suction vortices brings up a question I've had that maybe some of you could answer.

There is a video of a very small tornado in Alabama that sends cars rolling. Watching the video, it appears that the front of the car is seeing winds from the opposite direction as the back of the car, which to my uneducated eye looks as if it enhances the effect on the car by the tornado. Has there been much research done on the effect that torque plays in very small and tight circulations? I've thought about this quite a bit but have found little reference to it.

Here is the video I am referring to:


The references to the Yazoo City tornado possibly (or probably) having multiple vortices and the spotty damage had me thinking about it. Forgive me if it's too far off topic.

 

[Jeff Duda]

Jeff and Matthew's discussion and Shane's references to multi-vortex tornadoes and suction vortices brings up a question I've had that maybe some of you could answer.

There is a video of a very small tornado in Alabama that sends cars rolling. Watching the video, it appears that the front of the car is seeing winds from the opposite direction as the back of the car, which to my uneducated eye looks as if it enhances the effect on the car by the tornado. Has there been much research done on the effect that torque plays in very small and tight circulations? I've thought about this quite a bit but have found little reference to it.

Here is the video I am referring to:


The references to the Yazoo City tornado possibly (or probably) having multiple vortices and the spotty damage had me thinking about it. Forgive me if it's too far off topic.

You wanna see a tight circulation? Check out this video from Sweden in 2008. It shows you an example of the torque a very small tornado can put on an object like a tree:

 

[NickSeyour]

Based on damage Yazoo city tornado was a stronger EF4 then Bowdle nader. Far from EF5 .... damage is clear and no homes are swept of foundations or stuff of that nature.

 

[Bob Hartig]

Here is the photo I was talking about. This tornado will be familiar to anyone who chased the Bowdle storm. Some of the multiple vortices are obvious enough at first glance, but if you look more closely, you can make out more subtle vortex strands. Some of the larger sub-vortices may in fact consists of even smaller vortices. I'm aware that I could be just forcing my own perspective on what I'm seeing, so I welcome forum members' input, whether in support of or critical of my thinking.

 

[Jonathan Merage]

Bob,

I agree with your observations of multivortex "strands" within many tornadoes. I definitely believe (and science & footage has shown) that perhaps 99% of tornadoes and related circulations have this structure. Having witnessed the LaGrange tornadogenesis from up-close (pretty much beneath it) and of course the Bowdle storm, I know exactly what you are referring to.

Sometimes you can make out that spiraling "spaghetti-strands" appearance to the rain curtains inside the larger developing circulation. The LaGrange tornado was the first time I witnessed this phenomenon. The very fine, wispy rain curtains actually began circulating faster & faster as the tornadic circulation occluded. When I say that, I mean the ENTIRE strand, not just parts of it, which were then pulled inwards & condensed into the low-pressure core. Since tornadoes are basically organized & concentrated vorticity (both positive & negative--i.e. upwards & downwards) and computer simulations have hinted at this-- those fine, wispy rain curtains might get caught up in something similar to the circulating strands of bubbles in a plastic cylindrical centrifuge in a medical lab.
As the tornado intensified & pressure gradient tightened, the differential between the top (cloud base) & near-ground level winds would naturally increase the degree of vorticity & spin thus forming much finer "whirls" within the parent circulation that start to torque, as Wes mentioned.

MY belief from observation is that any limits on the number and intricacy or structure of these lesser whirls would depend on the size, structure, wind speeds/pressure gradient, and even forward speed of the tornado itself (relative to the larger storm/meso, to be clear).

 

[Adam Lucio]

Here is the photo I was talking about. This tornado will be familiar to anyone who chased the Bowdle storm. Some of the multiple vortices are obvious enough at first glance, but if you look more closely, you can make out more subtle vortex strands. Some of the larger sub-vortices may in fact consists of even smaller vortices. I'm aware that I could be just forcing my own perspective on what I'm seeing, so I welcome forum members' input, whether in support of or critical of my thinking.

*SPAM ALERT*

I have good video of this which can be seen on Bullseye Bowdle. I too was wondering if this is something that happens in most tornadoes. Even on the Albert Lea storm there were time I noticed several vorticies as opposed to one main circulation. Furthermore with that tornado it seemed to transition multiple times. It would widen out as an obvious multi vortex dust-bowl but then condense into a violent cone, but even when it did that one could see indications of smaller vorticies within it, especially when the very bottom of the tornado wasn't visually condensed on the ground.

 

[Terrence Cook]

Here is the photo I was talking about. This tornado will be familiar to anyone who chased the Bowdle storm. Some of the multiple vortices are obvious enough at first glance, but if you look more closely, you can make out more subtle vortex strands. Some of the larger sub-vortices may in fact consists of even smaller vortices. I'm aware that I could be just forcing my own perspective on what I'm seeing, so I welcome forum members' input, whether in support of or critical of my thinking.

The Bowdle storm had so many spectacular tornadoes of all sizes that I find it easy to forget the details of some of the lesser tornadoes, including the one that Bob pointed out. Thanks to his post and picture I very clearly recall the bizarre genesis and duration of that tornado. Changing shape, size and intensity quite a bit and was one of the more stationary tornadoes I have ever witnessed, from my vantage point anyways.

Also, the structure above the storm at the time of this tornado was nothing short of spectacular.

I wanted to share a series of frame grabs from a tripoded full HD camera... these give you a little better idea of what Bob is talking about, quite spectacular and very mesmerizing.

This tornado stands out from the rest due to the photogenic nature and dynamic changes it went through in addition to the bizarre appearance of these "vortex strands" as Bob worded it. Fascinating!

Thanks for bringing that up Bob.

 

[Kevin Crawmer]

Wow, this is a great conversation. Great input by everyone. Having been on Bowdle and Yazoo City I must say this is still a TOUGH choice for me.

Yazoo City was incredible. The radar signature, the inflow, the damage....everything. We didn't get a great visual as we were to the south (the only visual was if you were due east of it). The inflow was nuts. I believe on Jesse Risley's video you can hear the trees snapping next to us in the inflow. The pressure in my ears was nuts too. We were among the first on the scene and that is something that haunts me. Though the damage wasn't EF5, the human impact is haunting. We're talking people with mud and insulation caked in their mouths, eye sockets, ears, etc. Blood, broken bones, people that lost everything, injured babies, individuals paralyzed, etc. I'm sure I posted a few damage pics on the storm reports thread from that day. One thing that was different about this day was that the storm hit around noon.

Bowdle was breathtaking. We were fortunate to be on it from a puffy cloud off the dryline to its progression to the monster. It was beautiful, powerful, and very chaseable. Watching the high tension tower get ripped up in Weberpal's video is sick. The only damage we saw was a small farm that was hit...but not very bad. We were close to it when it was in it's massive wedge form and the power of that storm was amazing. Something that I will never forget. It was everything I ever wanted in a photogenic storm from stovepipe to cone to wedge to sunset/backlit needle. It was an incredible day, but I remember being very relieved to hear that it missed the town of Bowdle. Yazoo City is something I don't want to relive anytime soon.

Having seen both I cannot commit to either. I wish I had seen more of the Bowdle damage and then I could make a better judgement.

 

[Nathan Edwards]

Whilst my vote goes to Bowdle, I always think about the storms we were lucky enough to have avoid major populated areas which could well have been rated higher. The Medford Wedge quite possibly could have been rated higher whilst it was east of 81 looking at radar presentation and what little I could see of the back edge of the tornado as it moved east past me. The Montana killer tornado which wiped the farmhouse clean and tore up a bridge but missed everything else looked like a potentially violent tornado but as with Medford only attained EF3 rating. Neither storm has particularly clear video but radar and anecdotal evidence make me think they were capable of inflicting ef4 damage if strong enough structures were in their path.

 

[cdcollura]

Good day all,

I voted for Bowdle, SD because of the lack of forward speed and INCREDIBLE motion from a vantage point within a mile of the storm.

I was also on Yazoo (MS), but the visibility on it was poor, but the forward motion of 60+ MPH may have helped with its destructive power.

The Bowdle storm also went just north of a farmstead and south of major powerlines (during peak intensity). Despite disintegration / severe damage to these structures, the real core flow of the peak winds still missed these! EF-4? (or EF-5)? Who knows.

Yazoo was confirmed EF-4 because it hit the southern portions of the town in a heavily wooded residential area. Strongest or not, you cannot tell the people there who suffered losses.



Above: Link to the responses after Yazoo got hit.

Another interesting thing about the Yazoo tornado was its radar presentation. The divergence / velocity was more impressive than the Bowdle storm and extended very high up into the storm updraft, in incredible tilting / shear. The Bowdle storm was also impressive, but not as much as the Yazoo tornado by simply looking at it (the velocity couplets). This could also be affected by the distance to the radar site, attenuation, etc as well. Or, simply, not reflect the ACTUAL winds in that "mysterious" radar region between the beam "base" height and ground level.

 

[Pierre Pouzet]

I don't know if this one was considered to the Wadena tornado (I've not vote yet), but the most powerful tornado was (for me) the one in this vidéo :

Watch video >

2'49 !! Extreme oO

We can hear "that's an EF5" from storm chasers !