2004-05-22:Hallam, NE tornadoes

cdcollura

EF5
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Good day all,

May 22 of 2004 was another notable tornado outbreak / event. Two distinct supercell clusters developed along a warm-front / boundary and dryline bulge. One was near Mc Cook, NE and the other SW of Lincoln, NE, including the supercell that affected Hallam, NE with an F-4 (old scale) tornado at an astonishing 2.5 mile width!

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Above: Possible large (wedge) tornado southwest of Hallam, NE (before widening / strinking the town 10-15 minutes later) illuminated by lightning. This tornado / tornado cycles had a length of over 50 miles.

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Above: Radar image ... Tornado is the "hook" to the lower left part of the supercell near Wilbur, but also note the "vortex hole" in the HP storm. This was about the time the first annotated image (above this one) was taken.

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Above: Damage in Hallam, NE on May 23 during damage survey. This WAS a two-story home!

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Above: Large color-TV in roadside ditch, about a MILE away from any homes (or what was left of them). Anything in an F4 tornado (note, this was 2004, using the old F4 scale of 205-260 MPH) becomes airborne in the debris flow, even large appliances / vehicles.

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Above: Mangled pickup truck "deposited" in a field, about a half mile from any homes.

A full chase log on my account for May 22, 2004 can be seen in detail at the link below.

http://www.sky-chaser.com/mwcl2004.htm#MAY22

A short description of my log can be read here (below)...

May 22 - Outbreak and high-risk chase day in south-central Nebraska. Today was an extremely volatile and dangerous setup. We left Schulyer, Nebraska and headed south stopping in York to look at data and await break of the capping inversion. During initiation, we headed west on I-80 towards highway 281 and headed south as a line of storms fired to the southeast of on-going convection to our west. We headed east on highway 6 east of Hastings to intercept the storm and had to back out because the storm split and golfball sized hail began hitting us. We headed back west, then south to highway 4 to go back east. The southern split storm became a monster tornadic supercell producing multiple large tornadoes. A large wedge type tornado occurred south of the storm core, and was observed very faintly from behind the storm headed east. Damage was observed along the way (tornado path), including a demolished two story house! After that, we navigated along back-roads to get to the southeast side of the supercell. Several funnels were observed and another large wedge type tornado (possibly?) to the northeast of Beatrice, Nebraska along highway 77. Sure enough, a small town northeast of Beatrice (Hallam) had severe damage according to preliminary reports. We spend the night in Beatrice after all activity passed on to our east. Damage assessment required tomorrow ...

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May 22, 7:30 PM - Interception and observation of an EXTREMELY severe, tornadic, and dangerous supercell thunderstorm from east of Hastings, Nebraska to north of Beatrice, Nebraska. This storm was a monster supercell thunderstorm that began as a classic supercell and evolved to an HP supercell at least 30 miles across. The storm produced at least 6 cyclic tornadoes. The first was a large wedge barely visible west of the storm (we were too late because we aborted a northern divert around the core of the supercell). The tornado path was crossed where power poles were snapped, grass scoured off the hillside, irrigation equipment was mangled, and worst of all, a two-story house was ripped apart by the previous tornado. The storm produced inflow winds up to 60 MPH even 5 miles to the southeast of the storm. The storm had hail to 4 inches (but only sporadic golfball sized hail was seen as we tried hard to avoid the core at all costs). Lightning was continuous. Multiple funnel clouds formed around the storms RFD flank. The supercell acquired a full "stacked plate" appearance, but this time, it stretched across the entire sky. A large wedge-type tornado (possibly) was observed about 15 miles northwest of Beatrice as the storm passed by. A faint, low roaring (train) sound was noted with this feature. Later, preliminary reports of damage came in from that general area, which we were only a mile or so away from at the time of the possible tornado! This storm was part of a severe weather outbreak caused by a dryline punch, upper air support (jet stream and wind shear), strong low pressure system, and intense surface heating. Documentation was still photos, a camcorder, and audio. A PDS (Particularly Dangerous Situation) tornado watch was also in effect for this area until 11 PM CDT.

May 23 - Today we took a day off from chasing and spent an extra day in Beatrice, Nebraska to do vehicle maintenance and repair damage to the Weatherlab III weather station. After taking care of some minor issues, we decided to go with BNVN manager Doug Kiesling to survey the damage in Hallam and verify the tornado track. The damage swath was a MILE WIDE in some places, and a depressing scene of destruction loomed over what little was left of the town of Hallam. 95 percent of the town was totally disintegrated! We documented the damage with permission from authorities / residents and left due to the 8PM curfew. Tomorrow may be another chase day so we spent another night in Beatrice.

EDIT: I found this rather interesting read (a small snippet from it and the link to the story is below)...

"A 23-year-old bank receipt from Hallam, Nebraska turned up in Papillion 30 minutes after the tornado leveled the Lancaster County town 73 miles away Saturday night."

http://www.wowt.com/news/headlines/789817.html

Another estimate says the receipt / check traveled the 72 miles in 26 minutes ... Wow - Probably got lofted in the tornado, rode the high-velocity-core (150+ MPH updraft) to jet-stream level (2-3 minutes to 30,000+ feet), then (assuming 200+ MPH jet stream at 3.5 miles per minute), it should have reached 72 miles out in about 20 minutes. The remaining time should be the check "leafing" it's way back to earth (or faster if frozen in ice?)
 
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Damage survey
PATH LENGTH: 52 MILES
MAXIMUM PATH WIDTH: 2 1/2 MILES
Archived radar imagery and damage photos

I was not chasing this day, but my family and I were eastbound on I80 just north of the storm for a good distance. It seemed that each "Entering XXXX County" sign we would pass, the radio would sound the weather alert tone and we would hear a new tornado warning for XXXX County. Pulled off to the side of the road once to watch some violent rotation (in the air) just north of the interstate near York, but it didn't get its act together. It wasn't until later that evening, safely in Omaha, that I learned the fate of Hallam and the size of the monster we had been parallel to.
 
Was the radar image of this tornado very impressive? What I mean was it very well defined on radar indicating it was a definite tornado? Even though this tornado was rated F4, is there possibility it could have been an F5. Now the size does not matter and an F4 is nothing to sneeze but could it have been possibly stronger.
 
More on this event.

As I was with Chris (and Jeff Gammons, Amos Magliocco, among others), here is some fun stuff I have of that day as well:

This is a similar image to Chris's....hopefully it's easy to see the tornado as I played with it in photoshop to help the contrast.
IMG_4094text_web.jpg

Chris....check your time stamp though, I had a different time than you listed on your image. I coordinated the location and our position with the NWS survey (map below).

Here is a simulated (photoshop) view of the tornado when we were closest to it:
hallam_googlestreetview.jpg


Chase Map:
040522_chasemap.jpg

(more coming in a few minutes...looking for links)

Damage Path (the green transparent area showing the tornado path is taken directly from the NWS map):
hallam_damage_path_900.jpg


Some additional Photos:
IM007166web.jpg

Awaiting initiation. (L-->R: Gary Wellman's Highlander, Amos Magliocco's 4runner, and the Weathervine "WeatherBus")

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Chris (left) and Amos (right) discuss the extremely low pressure center....even before initiation this looked like it was going to be a bad day.

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Amos makes a U-turn to keep up with tornado (seen on right side of photo).

Later that night, while others rested at the Hotel (Victorian Inn....super great place), I ventured out to get some most excellent lightning video and photos.
IMG_4142web.jpg

This was taken around 1am or so along US Rt. 136 about 10 miles east of Beatrice, NE.
 
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Good day,

Chris....check your time stamp though, I had a different time than you listed on your image. I coordinated the location and our position with the NWS survey (map below).

Thanks a bunch, Jason ... I adjusted the time stamp to 8:20 PM CDT (rather than 8:30) ... With these "big events" 10 minutes means ALOT - Thanks again.

Excellent additions and annotations too, by the way!
 
I don't keep up on research papers, so this may not be an original thought, but storms like Hallam make we wonder if these massive longtrack F5 HP tornadoes that come right after sunset are not caused by some completely different storm dynamic than the 'typical' supercellular tornado. How in the world does a tornado get 2.5 miles wide? Same deal with Greensburg; 1.7 miles wide, longtrack F5 HP right after sunset. When I watch radar loops of the base reflectivity of these storms, I swear I can visually perceive the entire storm spinning around an axis.

Do researchers tend to look at these storms as being somehow "different" than typical HP supercells, or is it just typical HP supercell storm evolution taken to a much larger, more powerful scale?
 
Having observed the Hallam and Greensburg storms from infancy (pretty much "luck") and looked closely at the mesoscale environment of each, I can comment some on this... at least from a near-storm environment standpoint. One obvious commonality between the two was ridiculous combinations of low-level shear and total instability (for example, each case had a 0-1 km EHI right around 10 or 11 based on modified profiler/RAOB/model data!). The other commonality was the maintenance of a strongly surface-based environment (i.e. near-zero MLCIN and strong low-level CAPE) after dark, due to a relatively deep and very moist BL, relatively slow near-surface cooling, and modest capping aloft (e.g. 700 mb temps only around 8C... and the added benefit of elevated terrain in the Greensburg case). Add those two factors together, and the results can be very scary... and luckily they don't occur very often in tandem.

On the Hallam day, the low-level shear became pretty outrageous shortly after 23Z, with light southeasterly surface winds and the LLJ rapidly ramping up to 40-50+ kts... and 0-1 km SRH likely > 400 m2/s2 by the time the tornado was striking the Hallam area, per previous trends on the Fairbury profiler prior to the storm passing just N of it. Deep layer shear was pretty outrageous as well, far moreso than the Greensburg day, with profilers sampling 500mb flow as strong as 80 kt. This shear profile was present in an environment of very strong CAPE (~3800 J/kg per blended/modified OAX and TOP RAOB), and of course near-zero CIN and strong low-level CAPE. I haven't calculated the STP value for this (I don't use that parameter very often), but I can only assume it would be ridiculously large... further underlining how every parameter in that case was fully maximized... pretty rare, especially in an environment with no CINH.

As for why the storm morphed into an HP blob so quickly, I'm not really sure. High-level SR flow seemed pretty respectable for the Hallam event (35-40 kt per modified FBY profiler data), and I've certainly seen many other storms with that kind of sr-flow magnitude that stayed solidly in the classic cateogry of supercell. IIRC, some research on this topic (Rasmussen et al? don't quote me on that) uses 40 kt of high-level SR flow as the far lower bound for classic though, so who knows.

I don't keep up on research papers, so this may not be an original thought, but storms like Hallam make we wonder if these massive longtrack F5 HP tornadoes that come right after sunset are not caused by some completely different storm dynamic than the 'typical' supercellular tornado. How in the world does a tornado get 2.5 miles wide? Same deal with Greensburg; 1.7 miles wide, longtrack F5 HP right after sunset.
 
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This was a big day for Iowa aswell and I think maybe Missouri. A total of 36 tornadoes touched down in Iowa (to my knowledge) making this one of the largest outbreaks for the state. I had to take shelter in central Iowa twice in the afternoon. I stayed up late watching the storms and I was about to go to bed when a bow echo formed with a maximum wind gust at 106 MPH. A DOT truck was blown off the highway. I stayed up watching this bow echo become tornadic dropping tornadoes. After midnight I woke the family up as the sirens sounded again. Thankfully the tornado never made it to my town.

Another tornado outbreak occured on May 21 one day before the bigger outbreak. Several tornadoes touched down in northern Iowa and I remember seeing huge towers with these storms.This is the day that Bradgate IA was hit by a F2 tornado that damaged every building in town but one. The Sherriff if I remember right was injured by debree when trying to sound the alarm. The town sits in a valley so it is proven valley's do not save a town from a tornado. (There was a myth about that)
 
I was not in Nebraska to watch this action. However, a month later I was visiting my father in Lincoln and we decided to head down to Hallam to help with the cleanup effort that was going on. The town was all but leveled. One sight that I will never forget is seeing a house that was in pristine condition. Green grass, flowers growing in the window boxes, etc. Surrounding this house was complete and utter devastation. We ended up helping out on a farm near the Norris School District high school building - we could see it being worked on from where we were. The damage everywhere was on a scale that I have yet to see again. New Orleans was certainly much larger and there was more damage (I gutted houses there for a bit after Katrina), but the damage was not as devastating and complete as I saw in Hallam.
 
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