Question on widest tornado ever

I heard something earlier this year that there was a Tor this year that was over 2 miles wide and on the ground for something like 50 miles. Did anyone hear about this Tor? I went to a NWS Skywarn class last week and the meteorologist said the widest was 1 mile. Does anyone know any statistics to prove his statement differently?
 
I think the log in the NCDC database shows that they re-thought this. I think it did. They may of chopped an entire mile off.
 
Historical slant: Among the widest tornadoes might be the Sunray, Texas tornado from June 1971. Can't remember the width but I understand it was a pretty huge wedge, on the order of 1-2 miles. I know it definitely gets a high "grinder" rating (width divided by speed), perhaps the highest on record. The June 1995 tornado near Kellerville, TX was also pretty wide, I believe the largest Tim Marshall saw in his career.

Tim
 
Oddly enough, I can't find the Hallam tornado in Storm Data... You can search Nebraska, Tornado, 5/22/04 at http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dl...?wwevent~storms ... They have the many tornadoes that occurred on that day, but I can't find the Hallam monster... Perhaps it hasn't be submitted yet?

As the tornado crossed several county lines, each segment is listed seperately, but here is the link for the Lancaster County (Hallam) seg.

http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dl...howEvent~538517
 
Misleading

The NCDC summary for this event is a little misleading. It only states the width of the tornado as it crossed into Lancaster County near Hallam.

"The tornado remained nearly at this strength as it crossed into Lancaster county near Hallam with a damage path of around 1 1/2 miles."

The NWS summary from May states the following:

"THE TORNADO FROM WILBER TO NORTH OF CLATONIA TO HALLAM GREW TO ITS MOST INTENSE STAGE. THE TORNADO'S PATH WIDTH ALSO INCREASED TO AN UNPRECIDENTED TWO AND ONE-HALF MILES."

So has this tornado been "officially" declared 1.5 miles wide at its widest stage, rather than 2.5 miles wide? If so, I would think there would be a statement in the NCDC summary explaining that.

This needs to be clarified.
 
Hypothetically speaking, as I do not have direct access to pictures of the entire damage path, but with an F4 tornado (winds at or above 200mph in the funnel) it doesn't seem impossible that a 1.5 mile wide wedge could cause minor damage due to much weaker tornadic winds outside the actual funnel, possibly up to 1/2 mile?

Corrections to this theory would be greatly appreciated.

Thanks,
Sam
 
By the way, Storm Data and NCDC uses tornado segments which divide the tornado track by county to help verify warnings.

2640 yards is the width of the tornado, Storm Data uses, which is 1.5 miles wide, not the 2 1/2 miles in the preliminary survey reports. Interesting to see, why it was change, did they initially include damage from the RFD of the tornado.

I would contact the SOO and WCM of the Omaha office to find how out why.
http://www.crh.noaa.gov/oax

This is how the Hallam tornado looks in the final May 2004 Storm Data, for some reason, my computer could not paste it in format that they use. I had to type it up a bit diiferent, still contains the exact information from Storm Data.
Storm Data and Unusual Weather Phenomena May 2004

Location: Jefferson County
3 W Daykin to 3 N Daykin
Date: 22 May 2004
Time Local/Standard: 1830 to 1838 CST
Path Length: (Miles): 4
Path Width: (Yards): 440
Number of Persons
Killed: 0
Injured: 0
Estimated Damage
Property: 220K
Crops:
Character of Storm: Tornado (F1)
See description below.

Location: Saline County
6.5 SW Western to 3 E Wilber
Date: 22 May 2004
Time Local/Standard: 1838 to 1910 CST
Path Length: (Miles): 20
Path Width: (Yards): 1200
Number of Persons
Killed: 0
Injured: 8
Estimated Damage
Property: 20M
Crops:
Character of Storm: Tornado (F2)
See description below.

Location: Gage County
3 W Clatonia to 5 NE Clatonia
Date: 22 May 2004
Time Local/Standard: 1910 to 1930 CST
Path Length (Miles): 7
Path WidthL (Yards): 2640
Number of Persons
Killed: 0
Injured: 0
Estimated Damage
Property: 20M
Crops:
Character of Storm: Tornado (F4)
See description below.

Location: Lancaster County
1 S Hallam to 2 E Bennet
Date: 22 May 2004
Time Local/Standard: 1930 to 2005 CST
Path Length (Miles): 19.5
Path WidthL (Yards): 2640
Number of Persons
Killed: 1
Injured: 30
Estimated Damage
Property: 100M
Crops:
Character of Storm: Tornado (F4)
See description below. F73PH

Location: Otoe County
4.5 SW Palmyra to 1 WSW Palmyra
Date: 22 May 2004
Time Local/Standard: 2005 to 2010 CST
Path Length (Miles): 3.5
Path WidthL (Yards): 880
Number of Persons
Killed: 0
Injured: 0
Estimated Damage
Property: 20M
Crops:
Character of Storm: Tornado (F1)
See description below.

This long tracked tornado is often referred to as the Hallam tornado. It initially touched down 3 miles west of Daykin in northern Jefferson county. The tornado was rated an f0 or f1 in Jefferson county damaging farm outbuildings, grain bins and trees. From there the tornado crossed into Saline county southwest of Western and remained an f0 or f1 until it struck the southern portion of Wilber where it strengthened to f2. Roofs were blown off of homes just southeast of Wilber.

The tornado traveled from Wilber into Gage county, crossing the county line west of Clatonia where it grew to its most intense stage, f4. The tornado remained nearly at this strength as it crossed into Lancaster county near Hallam with a damage path of around 1 1/2 miles. Many well-built homes were demolished from Clatonia to Hallam, along with grain bins, farm sheds, and outbuildings. Many trees were destroyed or uprooted. Although Hallam itself escaped the strongest winds from the storm, which occurred just south of town, 95 percent of the buildings in town were either destroyed or severely damaged. The lone fatality from the tornado occurred in Hallam. The storm also toppled several hopper cars from a freight train on the west edge of town. In total 55 railroad cars were derailed.

From Hallam the tornado traveled east for several miles prior to turning northeast again just north of Cortland. The storm then tracked 2 miles north of Firth, severely damaging the Firth-Norris high school and a nearby middle school. School busses were tossed in this area. Several homes northeast of the schools were flattened as the tornado regained its f4 strength.

The damage path continued northeast to Holland and then to 2 miles north of Panama where the tornado weakened to around an f2 and the damage path began to narrow. The track then curved more toward the north, passing just south of Bennet where a few homes sustained f3 damage. After passing south of Bennet, the storm moved back to the northeast and began to weaken to f0 or f1 strength as it crossed into Otoe county southwest of Palmyra. The tornado finally dissipated 1 miles west southwest of Palmyra.

In total the tornado was on the ground or around 54 miles with a maximum intensity of f4. Besides the fatality, 38 people sustained injuries, 158 homes were leveled and 57 others were seriously damaged. The dollar amount of damage was estimated at 160 million, with 60 million of that agricultural including 100 cattle and 50 hogs lost. Some 150,000 acres of crop land sustained significant damage. The 5 counties were declared national disaster areas by Fema.
Mike
 
I have a hard time believing the Hallam tornado was ever actually 2.5 miles wide although I suppose it is possible. My unscientific guess would be that the damage path could have indeed been that wide but caused by a combination of the tornadic circualtion, RFD, and possible wobble of the track of the tornado, heck maybe even a strong inflow jet, I really don't know.

I did drive through the damage path east of Wilber on the way to another chase a few days later and can easily believe that it was 1.5 miles wide. Not too many may know, but there was another tornado in Southwest NE that was this wide in 1990.

http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dl...howEvent~156304

Those two are the widest I could find on my brief search of NCDC. Other then that I googled and found this link which says the widest was 1.8 miles in OK in 1947, which is before NCDC keeps records, btw. Anyone know if the Tornado Project books keep a list of the widest tornadoes?

http://www.usgennet.org/usa/ok/county/wood...ward/intro.html
 
By the way, back in 1971 (as Tom Grazulis mentions in his most recent book) the average tornado width was recorded, not the widest path width. It is quite possible that the June 9, 1971 tornado was wider than the Hallam tornado at some point. Just a little food for thought.

Gabe
 
I also have a hard time believing the tornado to be that large ... we do have video shot as the tornado was moving through Hallam from the south of town - through the lightning strokes you can make out what looks like a very large tornado - but it was probably about five miles away from our position, and very difficult to tell because of the lowlight conditions. Here's a vidcap of an earlier tornado from the same storm from southwest of Hallam by about 15-20 miles. Sorry for the quality ... looks better on TV.

[Broken External Image]:http://img.photobucket.com/albums/v143/mikeperegrine/HebronTornado.jpg
 
By the way, back in 1971 (as Tom Grazulis mentions in his most recent book) the average tornado width was recorded, not the widest path width. It is quite possible that the June 9, 1971 tornado was wider than the Hallam tornado at some point. Just a little food for thought.

Gabe

Surely they still don't do that? It would be the only explaination I could see why they would say Hallam was 2.5 and NCDC says 1.5. I don't measure tornadoes, I just chase them. :wink:
 
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
 
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
 
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.
 
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
 
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.
 
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)
 
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
 
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....
 
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."
 
Back
Top