Question on widest tornado ever

[mikegeukes]

Here is an explanation of the path length and path width that is used in Storm Data and NCDC Storm Events.
Source: Storm Data

# Path Length and Path Width

Path length and width are given for a tornado on the ground in the indicated county. When the tornado moves into an adjacent county another entry for path length and width is given. The total length is the sum of the lengths in each county. The width is the maximum width determined.

Mike

 

[Tim Vasquez]

If it appeared in this thread, I may have missed the tornado path width for Sunray (6/9/71). However Tom Grazulis' tome lists it at 2500 yards (1.42 miles). The previous comment about it being an average rather than a max width does bear looking into.

Tim

 

[Mike Peregrine]

One other thing I wonder about with Hallam is the absolutely INSANE wind from the RFD ... it was easily the most incredible RFD I've ever encountered. The dirt being spewed up behind the tornado was kicked hundreds of feet into the air, and then appeared to become caught up and circulated around the tornado at times. (I know it sounds weird ... but it was just really interesting watching the dirt wrap into the funnel.)

I wonder if the RFD could cause its own damage path up to a half mile to possibly even a mile behind the tornado - and if some of the damage could be misinterpreted, allowing for an enlargement of the path estimation. Couldn't it at least be possible that the angle of the RFD damage could meet up with the tornado track to make it appear to be a wider tornado? - I would not have wanted to be anywhere NEAR that RFD - it could have easily produced F1 damage all on its own, I'll bet -

What makes me think about this is actually just seeing Roger Hill's crazy RFD video from 2000 (?) again tonight on TLC ... the RFD appeared to be wrapping to the south of the tornado, but was wreaking it's own brand of havoc ... made me wonder if something similar was going on close to the Hallam beast.

 

[Gabe Garfield]

FYI:

From the SPC Tornado FAQ:

What was the biggest known tornado? The Hallam, Nebraska F4 tornado of 22 May 2004 is the newest record-holder for peak width, at nearly two and a half miles, as surveyed by Brian Smith of NWS Omaha. This is probably close to the maximum size for tornadoes; but it is possible that larger, unrecorded ones have occurred.

From the old SPC Tornado FAQ:

What was the biggest known tornado? Fittingly, it was in Texas -- specifically, in the high plains of the Texas Panhandle near Gruver on 9 June 1971. At times, the tornado was over 2 miles wide, with an average width of about 2500 yards. This is probably close to the maximum size for tornadoes; but it is possible that larger, unrecorded ones have occurred.

For the record, the book in which Grazulis reports that the average width was reported for the Gruver tornado of 1971 is called "Tornado: Nature's Ultimate Windstorm." By the way, it's a great book for anyone who loves tornado history. A very good read. http://www.islandnet.com/~see/weather/revi...s/tornadotg.htm

I wonder if the RFD could cause its own damage path up to a half mile to possibly even a mile behind the tornado - and if some of the damage could be misinterpreted, allowing for an enlargement of the path estimation. Couldn't it at least be possible that the angle of the RFD damage could meet up with the tornado track to make it appear to be a wider tornado? - I would not have wanted to be anywhere NEAR that RFD - it could have easily produced F1 damage all on its own, I'll bet -

Jeff S. and I can personally verify that there was a potentially damaging RFD in the southern vicinity of the tornado. We were receiving gusts easily into the 50-60 mph range (I'm underestimating here) immediately northeast of Firth, NE. I'm not sure what road we were on (some N/S road), but we started heading toward the circulation just to the NE of Firth. About .5 mi to .75 mi after we made our turn, the winds kicked up tremendously and small debris began to fall like snow. I've been close to the center of a tornadic circulation before, but I was never as scared as I was then. We hightailed it south and literally had to race the RFD for about 10 min (moving east) before the wind settled down to a manageable velocity. So in short, I do wonder if part of the reported 2.5 mile width was caused by the RFD.

Gabe

 

[Thomas Loades]

I don't know about the Hallam tornado, and just looking at the damage map gave me doubts about it (it may have been flanked by a "twisting downburst"), but anyway, some other events which may qualify:

•The Gruver, TX tornado of June 9, 1971, as already noted; it rated F2, and was up to 2 miles wide. The Sunray, TX event that day was 3/4-mile wide, and hit nothing but was once rated F4 on appearance alone. It has been downgraded to F1.

•The tornado that passed through Clearfield/Cameron/Clinton/Centre counties, PA, on May 31, 1985, had a path 2.2 miles wide at one point. It flattened oer 88,000 trees in the Moshannon State Forest, was rated F4, but caused no deaths or injuries (about the only respite that day).

•An F4 tornado that cut a 24-mile long path at an altitude of 10,000 feet in the Teton Wilderness, WY, on July 21, 1987, had a path between 1 and 2 miles wide, and the Tornado Project lists the average width at 2550 yards.

•The largest path I found, in Significant Tornadoes, seems to be an obscure event but a hell of a tornado nonetheless: on May 31, 1968, a tornado moving through Swisher and Hale counties, TX, had a path up to 3 miles wide, and "pushed a 3/4-mile-thick wall of sand ahead of it." It rated F3, and struck 4 farms.

 

[Larry J. Kosch]

Hallam tornado was a split!

I heard on the local news recently in Lincoln NE that a weather expert at UNL has done some research and came up with some surprising conclusions: 1. The Hallam tornado was, in fact, 2.5 miles wide at its biggest stage. 2. The Hallam tornado was the bigger of the TWO :shock: tornadoes that developed on that day. Apparently the second tornado died off right away and the bigger tornado went on past Wilber NE on its way to Hallam.

I will have to check around and see if I can find that research. This may shed some light on the tornado width mystery. 8)

 

[Jim Bishop]

I contacted Brian E. Smith who is the Warning Coordination Meteorologist at NWS in Omaha, Nebraska. I asked him about this whole issue with the size of the Wilber/Hallam tornado. I had full confidence in the original NWS survey. However I was disturbed when I read NCDC's unusual conclusion. Brian said:

"There is a mistake in NCDC site. It should be 2 1/2 miles wide. I couldn't believe it. It was basically a mesocyclone on the ground at that point...."

If you are looking for visual evidence, please visit my website. We have footage of the tornado from the north just east of Wilber near it's widest point. While the clip quality is poor, it does shed light on the subject.

Jim

 

[Joel Wright]

I heard that "the great tri-state" tornado had an enormously wide track. I'm not sure if that's true or not, but I could have swore I read or heard that somewhere....

 

[mikegeukes]

Some stats on the March 18, 1925 Tri-State Tornado
http://www.crh.noaa.gov/pah/1925/ss_frame.html

Mike

 

[Thomas Loades]

According to the ST entry on it, the Tri-State was 2–3 miles wide in SSE Missouri, which may be because the funnel was surrounded by downbursts, or two separate funnels were present (as opposed to a large multiple-vortex tornado). It "was probably a double tornado for 3 miles near Biehle."

 

[Dave Crowley]

We have actual footage of the tornado as it was N of Daykin, before we lost it in the rain and bad roads. http://stormguy.com/may22_04.htm
There are also video clips of it BEFORE dark, and up close.
I've also been skeptical of the reports, mainly because we experienced nearly 100 mph winds in the RFD, a mile away from the tornado, as well as power flashes and amazing things going on in the dirt.

 

[Bill Hark]

I was also on that storm (chasing with Jeff Piotrowski). We never got a good view of the tornado as it was dark and partially wrapped in rain. From the edge, the storm was absolutely amazing. The whole storm was visible rotating; a giant gray cylinder towering thousands of feet into the air. It was black underneath. At the time the tornado struck Hallam, we were viewing the storm from the southeast. I never measured the windspeed but I would estimate the inflow at 60 to 70 MPH. I have never experienced inflow that strong. We drove north but were cut off before we could reach the east option. I observed debris flying into the storm while heading north and decided to turn around and blast south. A couple minutes later, Jeff also turned around. (live to chase another day!) Although I quote the 2 and half mile wide statistic on my website, I suspect a lot of the damage is from inflow and RFD. I am assuming the NWS damage teams can distinguish between the actual tornado and RFD/inflow.

Here is my full account with images:

http://www.harkphoto.com/05222004.html

Here is a survey map of the damage path:

http://www.harkphoto.com/hallammap.jpg


Bill Hark