2011-04-09 DISC: NE/IA

[Mike Smith]

I have written a tribute to the meteorologists and chasers at: http://meteorologicalmusings.blogspot.com/2011/04/miracle-at-mapleton.html

This is the type of storm that used to kill dozens. Now, the lack of deaths is just a sidenote in the news coverage. I want to take a moment to celebrate the work of the National Weather Service in Omaha that issued the warnings, the Storm Prediction Center in Norman that issued the tornado watch, and the storm chasers that reported the position of the storm and then helped in the rescue effort.

Tremendous work last night!!

 

[Doug Drace]

4/09/11 DISC: NE/IA

I didn't get to chase this risk due to work, but I know everyone who did, especially on the Long Track Tornadic Supercell that produced the Mapleton Tornado along with numerous others, most certainly had a spectacular day!

All I could do is sit at home and enjoy the amazing radar and satellite presentation of that powerful supercell. I just wanted to post this amazing animation from the Visable Satellite not long after things got kicked off in E NE/IA. What is most incredible about this loop is the very noticable storm scale rotation through the Anvil level of the main Supercell, but also the storms which developed behind it! A perfect example of powerful wind shear in the Plains!

 

[Chip Redmond]

Preliminary storm surveys.

From Des Moines:
http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=dmx&storyid=66515&source=0

From Sioux City:
http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=fsd&storyid=66507&source=0

In the storm surveys their seems to be many crossing paths over a very small area. Would be interested to know if these were all at the same time or from different storms. I haven't had time to look at archived radar to see where the other storms crossed in relation to the earlier storms but it would be really interesting to see if there was at least a large multivortex on the ground. Going to take alot of time to go back over these, my images, and our path to determine what tornadoes I was seeing at what time. What a crazy night!



Chip

 

[Jeff Duda]

I included this image in my post in the REPORTS thread, but I'd really like to get multiple opinions on the feature; it looks very suspicious to me, and I didn't even see it until I ripped the image off of my camera after I got home last night. The image was taken from either just west of, or north of Schleswig shortly after 8 PM, looking northwest.

Whatever the circled feature is, it looks to be in the correct place relative to the large RFD clear slot to be a tornado, but I didn't get far enough north or west to tell for sure. Was anyone closer to Ida Grove or Arthur to conform or deny my belief that this may be a tornado? The Sioux Falls office did include a tornado southwest of Arthur in their PNS, which would be very near where this picture was taken: http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=fsd&storyid=66507&source=0

 

[J Trueblood]

I was just north of Denison. It was definitely a tornado. I didn't get an image of it, but there was a tornado on the ground north of Schleswig. I remember it very clearly because I couldn't say the name of the town no matter how many times I tried.

 

[cstrunk]

Jeff, that most certainly looks like a large tornado. If you look closely, you can barely make out the left edge of the funnel. 99.9% sure that is what we're looking at here.

 

[Kevin Walters]

Looks like a tornado to me.

 

[Jordan Hartley]

IMO, without a confirmed tornado and a time pinning the report and the photo near where this photo was taken I dont think you can hang your hat on the photo. Dont get me wrong, its a great shot if that is indeed a tornado. Its obviously very near or past sunset and if we can get this confirmed thats a hell of grab Jeff. But, imo what we are looking at is a very wet downdraft or microburst falling from the updraft into the rfd as the rounded bottom of surging air and precip are beginning to slam the surface. If ive seen one ive seen a thousand of these beautiful and powerful phenomenon. Very awesome to see at night when you got elevated bases and a very well lit up sky. They surge out the base of updrafts at night during high wind events and thats a sight! From your vantage point Jeff I think its a coin flip.

Whatever the circled feature is, it looks to be in the correct place relative to the large RFD clear slot to be a tornado, but I didn't get far enough north or west to tell for sure. Was anyone closer to Ida Grove or Arthur to conform or deny my belief that this may be a tornado? The Sioux Falls office did include a tornado southwest of Arthur in their PNS, which would be very near where this picture was taken: http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=fsd&storyid=66507&source=0

Heres a few links that might help my argument.

http://www.google.com/imgres?imgurl...tgfd5rWRAw&page=1&ndsp=60&ved=1t:429,r:23,s:0

http://www.google.com/imgres?imgurl...tgfd5rWRAw&page=1&ndsp=60&ved=1t:429,r:13,s:0

http://www.google.com/imgres?imgurl...&ndsp=60&ved=1t:429,r:0,s:0&biw=1920&bih=1017

Without the first photo link i wouldnt be able to confirm or argue a confirmed tonado in the second photo link. Any comments on my observations? Also Jeff, did you see or get photos of power flashes near this feature?

 

[Scott Hammel]

IMO, without a confirmed tornado and a time pinning the report and the photo near where this photo was taken I dont think you can hang your hat on the photo. Dont get me wrong, its a great shot if that is indeed a tornado. Its obviously very near or past sunset and if we can get this confirmed thats a hell of grab Jeff. But, imo what we are looking at is a very wet downdraft or microburst falling from the updraft into the rfd as the rounded bottom of surging air and precip are beginning to slam the surface. If ive seen one ive seen a thousand of these beautiful and powerful phenomenon. Very awesome to see at night when you got elevated bases and a very well lit up sky. They surge out the base of updrafts at night during high wind events and thats a sight! From your vantage point Jeff I think its a coin flip.



Heres a few links that might help my argument.

http://www.google.com/imgres?imgurl...tgfd5rWRAw&page=1&ndsp=60&ved=1t:429,r:23,s:0

http://www.google.com/imgres?imgurl...tgfd5rWRAw&page=1&ndsp=60&ved=1t:429,r:13,s:0

http://www.google.com/imgres?imgurl...&ndsp=60&ved=1t:429,r:0,s:0&biw=1920&bih=1017

Without the first photo link i wouldnt be able to confirm or argue a confirmed tonado in the second photo link. Any comments on my observations?

Very interesting point about this. At first glance I thought tornado, no doubt but I never considered the chance of a microburst/downdraft simply because it seemed like you couldn't go anywhere without running into a tornado last night. Ultimately though, I think from the distance and it being night time it probably isn't conclusive. One hell of a shot, I can conclusively say that! It is in the right area of the storm structure for where a tornado should be though...hmm? Like I said, either way it's a great shot. Any damage surveys from the area done today or corroborating reports at the same time from last night?

 

[Chip Redmond]

When the down/microburst reaches the ground the uppermost part becomes much thinner than the rounded edges of the burst. With Jeffs photo, the feature is more cone shaped than rounded. Granted the burst could have that appearance when initially leaving the cloud, it is quite vertically elongated to be one. From the nature of the supercell and its capability to put down that many tornadoes, I would venture to say its just that.

I may be a bit biased as I think I have a shot with the same looking feature and the bolt coming down but just a bit further back. We did see it lower slowly and have debris just before the time of the image. Rain wrapped around shortly thereafter as well. If I remember right, this was the first of numerous tors after dark from the cell.

I will look more in deptth when I edit and do a write up tomorrow.

Chip

 

[jshields]

anybody notice this in the preliminary storm survey damage?

..SURVEY FOR POCAHONTAS COUNTY, IOWA...

THE FOLLOWING IS A PRELIMINARY ASSESSMENT FOR THE DAMAGE THAT
OCCURRED OVER POCAHONTAS COUNTY ON APRIL 10, 2011.

* EVENT DATE: APRIL 10, 2011

* TORNADO NUMBER 1

* ESTIMATED START TIME: UNKNOWN

* EVENT TYPE: (EF2) TORNADO

* EVENT LOCATION: TORNADO BEGAN 4 SW OF VARINA AND CROSSED THE
COUNTY LINE AND ENDED 4 NW OF POCAHONTAS NEAR WARE

* PEAK WIND: 125 MPH

* AVERAGE PATH WIDTH: 2-3 MILES WIDE

* PATH LENGTH: 16 MILES LONG

* INJURIES: UNKNOWN

* FATALITIES: NONE KNOWN

* DISCUSSION/DAMAGE: IN VARINA A CHURCH GYMNASIUM COLLAPSED.
AN OLDER HOUSE COLLAPSED AND WAS MOVED OFF OF ITS FOUNDATION.

it's saying the AVERAGE width of the tornado was 2-3 miles wide over a 16 mile long path. does that seem possible?! i know there were some big wedges going on, but to average 2-3 miles wide for that long is truly amazing. that would have to put it up there with one of the largest tornadoes, right? maybe i'm underestimating the number of times i have seen this, but once a tornado hits 1-1.5 miles wide and larger that is a pretty rare. any thoughts?!

 

[MatthewCarman]

I only remember 1-2 tornadoes reaching 2.5 miles wide including the Hallam Nebraska tornado. NC may have had a 2.5 mile wide tornado but I am not sure about that one. An average path of 2-3 miles wide is impressive.

Anyone who says Iowa is bad for chasing is probably rethinking that right now. This is the second tornado event of the year for Iowa and it's only April.

 

[Danny Neal]

I am only focusing on this one "hybrid-nado". When I first saw it developing under the clear slot I thought for sure it was just an RFD gustnado and/or blowing dust. As we proceeded in its' direction we noticed cloud base had increased but still wasn't extremely significant. We pulled off a half mile down the road and noticed a funnel cloud dropping out of the high based meso. At this point I believe either a tornado or a landspout formed. The problem I am having is the fact that there isn't much in the way of surface rotation. There was a hint of some but mostly the mass of dust drifted ESE across the road. With such a clear cut funnel overhead I am in a quandary. Was this just a funnel cloud with the rfd kicking up dust to give it the illusion of a dust whirl? Was this just a gustnado and the funnel was just the best scud impostor I have ever seen? Or was this a tornado. We were half a mile away from it and saw cloud base rotation (albeit weak) and surface rotation (weaker). I would like to get some input. I am currently sending NWS OAX this video per their request as well.

 

[Andy Jackson]

I am only focusing on this one "hybrid-nado". When I first saw it developing under the clear slot I thought for sure it was just an RFD gustnado and/or blowing dust. As we proceeded in its' direction we noticed cloud base had increased but still wasn't extremely significant. We pulled off a half mile down the road and noticed a funnel cloud dropping out of the high based meso. At this point I believe either a tornado or a landspout formed. The problem I am having is the fact that there isn't much in the way of surface rotation. There was a hint of some but mostly the mass of dust drifted ESE across the road. With such a clear cut funnel overhead I am in a quandary. Was this just a funnel cloud with the rfd kicking up dust to give it the illusion of a dust whirl? Was this just a gustnado and the funnel was just the best scud impostor I have ever seen? Or was this a tornado. We were half a mile away from it and saw cloud base rotation (albeit weak) and surface rotation (weaker). I would like to get some input. I am currently sending NWS OAX this video per their request as well.

Considering how the Mapleton tornado visually formed, I'd say what you saw here was an early iteration to what was to come.

 

[Nick Nolte]

Danny, we saw several occurrences of exactly what your video shows. As the storm moved across the hills, this exact same feature was visible to us on three separate occasions while the cell was still west of Mapleton. I'd have to check logs to see exactly where we were at the time. We were also on the fence as to whether it was a tornado or a gustnado or whatever. Given the appearance of the Mapleton tornado, especially at the beginning of it's life cycle, I tend to agree with Andy, that they were probably tornadoes, but it is hard to say for sure.