twin tornados in Nebraska

[klw]

http://thevane.gawker.com/check-out-these-incredible-twin-tornadoes-in-nebraska-1591691504

 

 

 

 

A storm in Nebraska produced an extremely rare pair of tornadoes this evening as it tracked through the northeastern part of the state. Multiple vortices are common in the strongest tornadoes (think Joplin), but two large, distinct tornadoes side-by-side like this is almost unprecedented.

Numerous storm chasers are reporting "catastrophic damage" and serious injuries as a result of the tornadoes.

 

 

 

http://www.nbcnews.com/news/weather/nebraskas-deadly-twin-tornadoes-devastate-pilger-stanton-n132846

Video at this story.

 

[Hoosier]

There's been some amazing footage from yesterday.  Regarding the double tornadoes, I immediately thought of what happened in northern Indiana on 4/11/65 that resulted in those iconic photographs but that was a case of the vortex splitting which seems to be different than what happened here (at least I haven't seen footage from yesterday of one large funnel splitting).

[Ed Lizard]

All I know is that they didn't seem to be rotating around a common center or each other from video I've seen, and both were cyclonic.

 

 

I have seen movies of tornado pairs where one was anti-cyclonic.  Not the case here.  And the video I saw yesterday, you could see one was multiple vortex.

[Chaser25973]

How rare is this event? I can't think of a time where there were twin tornadoes that were so close together and a part of different vorticies? What causes this rare phenomenom?

[BuffaloWeather]

 

The brief moment of THREE TORNADOES on the ground north of Pilger, NE

[BrianLaverty]

I know its not, but that picture of the 3 tornadoes looks so fake.

[bdgwx]

Is there any video that would corroborate that picture showing 3 tornadoes?

[Hoosier]

It'd be nice if there weren't trees in the way on the left.  Curious about what that dot is above the tree line on the far left.

[SharonA]

Considering how many chasers and lenses were on those tornados at that time, probably yes, but I don't know offhand (I've not gone out and looked at lots of video, however).

 

The NWS preliminary survey mentions a third tornado -

 

[klw]

It'd be nice if there weren't trees in the way on the left.  Curious about what that dot is above the tree line on the far left.

my guess is the dot is something on a windshield

[Ellinwood]

Tornado Trackers is the only chase group that claims it to be three simultaneous tornadoes. ALL of the other chasers, including those who had better views of the tornadoes and the third wall cloud, say that there was NOT a third tornado occurring at the same time.

[bdgwx]

On the other hand there are a couple of volume scans that do show 3 distinct couplets (and possibly 4) on the radar. So I think we do have radar corroboration, but I'd like to know if all 3 of those actually translated into tornadoes on the ground at the same time.

 

[Jonbo]

_{If the picture is verified as legitimate, my opinion due to the trees in the way and from other reports is 2 tornadoes on the ground, is the third on the far left is a wall cloud. Which itself is still absolutely insane because it tried getting 3 at the same time without the existing 2 cycling.}

[bdgwx]

_{If the picture is verified as legitimate, my opinion due to the trees in the way and from other reports is 2 tornadoes on the ground, is the third on the far left is a wall cloud. Which itself is still absolutely insane because it tried getting 3 at the same time without the existing 2 cycling.}

 

I'm with you. I think the picture may be legit, but I too I'm leaning towards the far left just being a wall cloud.

[bdgwx]

This video at about 1:30 - 1:45 does show 3 large mesocyclones, but only 2 tornadoes from what I can make out. It appears like this would corroborate the picture above except that only 2 of the 3 mesocyclones had tornadoes.

 

This video at the 0:22 mark makes it hard to deny that there were 3 simultaneous touchdowns at some point in that cell's lifecycle, however.

[Jonbo]

That video at 22 second mark should end the discussion of.3 simultaneous touchdowns at once. Even though it was for only a few seconds.

[Ed Lizard]

That video at 22 second mark should end the discussion of.3 simultaneous touchdowns at once. Even though it was for only a few seconds.

The brief tornado didn't look anything like any of these 3 large tornadoes, however.

 

[Ellinwood]

I've reviewed the video many times and can't seem to confirm if that little dust-up was actually a tornado, though it's somewhat convincing. Hard to tell with shaky, brief glimpses of it.

NWS reaffirms their position: https://twitter.com/markellinwood/status/479912541783470082

@NWSOmaha: No evidence of 3 concurrent tracks.

[AtticaFanatica]

JMO, but it looks to me that there was a ground circulation there.

[Sunny and Warm]

JMO, but it looks to me that there was a ground circulation there.

Agree that there was a 3rd tornado touchdown.  Whether the NWS survey team found the spot it hit is irrelevant when you have clear visuals that it did indeed touch down with dust debris evident.  I also have to say that without firmer verification otherwise that the pic of the three massive tornadoes is a fraud.  

[bdgwx]

The brief tornado didn't look anything like any of these 3 large tornadoes, however.

 

 

You're absolutely right. The Dan Melby video must have been shot at an earlier point the cell's lifecycle. The first video at the 1:37 mark does show 3 large wall clouds though and could be at the same moment the TornadoTrackers picture was captured assuming it is legit. They did post an update on their Twitter feed apologizing for claiming it was 3 tornadoes. They now believe it was only 2. It would be nice to get some definitive confirmation on its authenticity either way.

[Jonbo]

*edit*

 

'This Chaser Chick's Adventure' did post a legitimate picture on Facebook when it was close to producing 3 concurrently. I can see how this while out chasing would cause confusion with the third on the left being a very low wall cloud.

 

https://www.facebook.com/ThisChaserChicksAdventures/photos/a.771857422853844.1073741843.554408081265447/771857436187176/

[bdgwx]

Nice find Jonbo. I think that does make the TornadoTrackers photo more likely to be authentic.

[Ellinwood]

Nice find Jonbo. I think that does make the TornadoTrackers photo more likely to be authentic.

Trackers' pic IS authentic. It just doesn't show the three tornadoes that they claim it does. (Ground circulations are obscured)

[Normandy]

I'm a casual follower of weather and would love to learn the dynamics behind something like this occurring.  From my limited understanding of low pressure systems/cyclones, would the proximity of these mesocyclones hinder one another.  Wouldn't one choke of inflow of the other?

 

I don't think i've ever seen two violent tornadoes so close to one another like this, especially both being produced by the same supercell.  Perhaps a red-tagger/knowledgeable poster can school me.

[Chaser25973]

bump - can any red tagger please explain how this occurs? Thanks.

[SkyOdyssey]

Other photos confirm three simultaneous tornadoes from a different vantage point. All such images I've seen show the third tornado as small, however, and I too am suspicious of the original photo suggesting three large tornadoes.

 

As for precedent events, simultaneous tornadoes are not that uncommon, however they tend to be from a hand off situation in which a previous tornado is dissipating as a new tornado (from new low-level mesocyclone) is maturing. This is the case with the Heston/Goessel KS tornadoes of 13 March 1990 when a F5 dissipated and eventually merged into the newly developing tornado which almost immediately increased to F5 intensity. The iconic Dunlap, IN example from 11 April 1965 was a case of large subvortices within a single multivortex tornado per Fujita. The violent Wichita Falls tornado of 10 April 1979 also showed this kind of behavior although it was not caught so photogenically as during the Palm Sunday outbreak. See http://www.srh.noaa.gov/images/oun/wxevents/19790410/tornado/wichitafalls/wells05.jpg from http://www.srh.noaa.gov/oun/?n=events-19790410 .

 

There is no case I am aware of where two large tornadoes were in such proximity or over such a long period. There may been some Fujiwara interaction. Other examples of simultaneous tornadoes include separate supercells some distance apart where high visibility afforded views. Storms can have multiple low-level mesocyclones/tornadocyclones and multivortex mesocyclones (MVMCs) and this storm will be intriguing to study in the years to come. Certainly unprecedented is that the following two days also produced simultaneous tornadoes in close proximity and that these occurred within the same region.

[AtticaFanatica]

bump - can any red tagger please explain how this occurs? Thanks.

 

The process is called cyclic tornadogenesis, whereby, in some cases, one tornado weakens and dissipates before or as a new tornado is forming. The original tornado moves away from locations that are favorable for tornado maintenance, often heading more toward the north or northwest for a storm moving east or northeast (so it moves west relative to the storm). In this part of the storm the tornado usually does not have access to buoyant, rotation-rich air suitable to keep it going. Meanwhile, the new tornado usually forms along or near a bulge in the rear-flank gust front, a boundary separating relatively cool westerly outflow air from relatively warm easterly inflow air. Along this boundary, you often have rotation rich air and convergence which are vitally important for tornado formation. Once this new tornado forms, the process may repeat itself again. It is not atypical to have both tornadoes co-existing for a period. It is unusual for both to maintain strong intensity or for them to interact or for there to be three at one time. A third tornado probably requires some additional mechanism or some corollary to the above ideas

 

It is not totally understood exactly why this happens. It has been hypothesized that a tornado that moves in a different direction from the parent storm because of the surrounding flow plays a large part. In other words, if there is weak storm outflow and strong storm inflow, the original tornado can be advected away from the locations suitable for its maintenance where it eventually dissipates and the new one forms. The lack of outflow is largely an internal storm mechanism, however, though anecdotal, storms days like this one where there were several cyclic supercells in a similar area also provide some circumstantial evidence for the idea that there is something unique in the near-storm environment that's important as well.

[das]

No comments, just adding a HD video from the south side (opposite from original vid at the top of this thread) as the tornado hits Pilger.  From Timmer:

 

https://www.facebook.com/photo.php?v=10152498787374169

[klw]

More videos showing up

With this jump to 1:40