What do you think of when you think of Nebraska tornadoes? Is it the Omaha tornado of 1975? Night of the Twisters in Grand Island? Pilger in 2014? The recent tornadoes in eastern Nebraska earlier this month? Maybe it is the tornado which is the subject of This Week in Weather History, the Hallam tornado on May 22, 2004.
This tornado was significant for many reasons, its length of over 50 miles, the enviornment it spawned in, or its massive width. In fact, the Hallam tornado was considered the widest tornado on record until the El Reno OK tornado on May 31, 2013. In this installment of This Week in Weather History, look back at one of the more famous Nebraska tornadoes.
MAY 22, 2004: AN ATMOSPHERIC POWDER-KEG
It's not often that severe weather ingredients come together this perfectly to spawn such a violent tornado, but on the afternoon of May 22 they did. A stationary front was sitting along I-80 in Nebraska into Iowa. This front separated temperatures in the 60s over northern Nebraska and temperatures in the 80s over southern Nebraska.
The day before, a cluster of thunderstorms rolled across northeast Nebraska into Iowa. This cluster of thunderstorms threw down what is known as an outflow boundary, which is rain-cooled air rushing away from thunderstorms. By the morning of May 22, this outflow boundary had been thrust into northern Kansas. This outflow boundary slowly weakened through the day, but the linger effect was a more ripe environment for severe weather in southeast Nebraska.
In northwestern Kansas, an area of low-pressure was slowly strengthening. It would not move that far to the east, keeping southern Nebraska and northern Kansas in the prime region for the possibility of explosive severe weather.
The final factor which came into play was a layer of dry air which overspread the warm air at the surface, this is known as the cap. The cap acts as a lid on the atmosphere, preventing warmer air from rising to create thunderstorms. What this allows the atmosphere to do is basically cook, the energy in the atmosphere builds throughout the day. Once the cap begins to erode, either by the presence of a cold front or the heat of the day, it makes the air that much more prime for explosive storms.
BEFORE HALLAM: MAY 22 IN NEBRASKA
The first storms of the day began developing near the Nebraska/Kansas/Colorado intersection by the early afternoon. These storms quickly went severe, then tornadic as they continued eastward through southern Nebraska. One supercell produced multiple photogenic tornadoes near Beaver City, this supercell would continue to near Hastings, where it dropped an F-2 that missed the town of Fairfield in Clay County by a few miles. The storm eventually brought baseball size hail and 90 mph winds to York County, causing damage in the region.
In eastern Nebraska, one supercell developed near Columbus and quickly went tornadic. This storm rode down US 30 through Platte, Colfax, Dodge, and Washington Counties. A brief tornado touched down southwest of Schuyler. In Schuyler, hail upwards of 3" in diameter caused damage. The storm did its worst damage in Fremont, particularly on the northern side of town. Hail up to 4" in diameter, bigger than baseballs, smashed windows and roofs in Fremont. At the Walmart on the east side of town, an F-1 tornado tore the A/C unit off the roof, dropping it on an SUV parked below. No one was in the SUV at the time.
Omaha fortunately would be missed by those storms, but thunderstorms quickly developed on the metro. These storms were efficent rain makers, dropping several inches of rain over top the metro, leading to flooding concerns through the night.
THE HALLAM TORNADO
While those previously mentioned events were ongoing in central and eastern Nebraska, southeast Nebraska was still storm free. This was due to the aforementioned cap, but as the clock approached 6pm that would change. The cap allowed the atmosphere to build up energy, and when it was released the consequences would be major.
It began over Thayer County, along the Kansas border southwest of Lincoln. A thunderstorm went from a small shower around 6pm, to producing 2" size hail in Hebron at 6:30, and its first tornado by 7pm. This first tornado completely destroyed a home near Belvidere, and was rated F-2.
As the storm moved into northwest Jefferson County, the tornado which would grow to strike Hallam touched down near Daykin. In Jefferson County, the tornado remained relatively weak as it damaged a few farmsteads before crossing into Saline County.
As it crossed into Saline County, it originally remained weak until reaching the outskirts of the county seat of Wilber. Although it missed the town, it skimmed the southern side of town where a few homes and businesses were damaged. One storm chaser was caught in the town when the tornado hits, producing this dramatic video where the building's front gets destroyed. Just a mile south of Wilber, several homes lost their roofs.
As it continued east of Wilber towards Hallam, the tornado both grew in intensity and in width. The tornado reached an astounding 2.5 miles wide, which at that time was the widest tornado in United States history. It has only been surpassed by the El Reno Oklahoma tornado on May 31, 2013 which was 2.6 miles wide. To put the width in perspective, the tornado's diameter would be between the Old Market and 42nd St in Omaha, or from the CHI Health Center to the Henry Doorly Zoo.
As it crossed into northwestern Gage County, near Clatonia, it produced its worst damage. At F-4 intensity, with wind speeds over 200mph, it destroyed many farmsteads in the county. The tornado continued at F-4 intensity as it crossed into Lancaster County, heading right for the community of Hallam.
A town of 275, founded in 1892, Hallam sits in far southern Lancaster County near the Gage County line. That night, many residents were going about their business when the roar began. Those who were not already in basements swiftly ran to them as the tornado swallowed the town hole. Around 95% of Hallam suffered severe damage, with several homes destroyed. One resident, a woman in her 70s, was killed. She would be the only fatality in the entire length of the tornado.
The tornado passed east of Hallam, missing other communities in southern Lancaster County like Hickman, Firth, Panama, and Bennet. Despite missing the towns, the tornado made a beeline for Norris High School. The last day of classes was the day prior, Friday May 21, meaning the building was largely empty when the tornado hit. One teacher was present, as were 11 people who took shelter, all survived. The school suffered major damage, the roof of the auditorium was destroyed, the football field damaged, and the school bus shed housing 30-40 buses was destroyed. School buses were tossed across the school like toys, including some which had fallen on the track.
The tornado spent its last gasps in Otoe County, lifting near Palmyra after its 60-mile path of destruction. The storm complex went on to produce a few more tornadoes and 80+ mph winds over Cass and Otoe Counties before weakening in southwest Iowa.
VIDEOS: Here, here, and here.
THE AFTERMATH
In the immediate aftermath, the Governor of Nebraska at the time, Mike Johanns, toured the area. He claimed it was some of the worst damage seen in Nebraska to date. The Counties of Jefferson, Saline, Gage, Lancaster, and Otoe Counties were declared disaster areas by the federal government. Damage is estimated in the ballpark of $160 million.
Over the next few months, the residents impacted rebuilt and cleaned up. Today, Hallam still hosts a population of over 200. The scars of the tornado are no longer visible, and the communities in southeast Nebraska are continuing to chug along today,
