| Fujita-Scale: | F4 |
| Winds-Prefix: | ~ |
| Winds: | NaNmph |
| Year: | 2004 |
| Deaths: | 1 |
| Injuries: | 38 |
| Damages: | 160220000 |
| Areas: | Nebraska (Jefferson, Saline, Gage, Lancaster, and Otoe counties) |
During the afternoon of May 22, 2004, a long-track F4 tornado formed during a tornado outbreak[1] and tore through multiple counties in southeast Nebraska. The tornado damaged many towns along its path, but its most significant destructive effect occurred at the town of Hallam. The Hallam tornado is recognized by NOAA as the second-largest tornado on record, peaking at wide at Hallam, behind only the 2013 El Reno tornado.
The Hallam tornado formed west and northwest of Daykin at 7:30 pm CDT at an F1 intensity on the Fujita Scale. One satellite tornado, rated F1, formed and quickly dissipated northeast of town. The main storm turned and traveled east-northeast from Daykin to a point south-southeast of Western and then to about north of Swanton. During this time, the tornado fluctuated between F0 and F1 in intensity, damaging farmhouses and silos. The tornado remained confined within the F0-F1 range until it hit southern Wilber, where it intensified to F2 strength and blew roofs off of structures. The tornado continued east-northeast, grazing the east side of Wilber as it moved towards Clatonia. Here it is estimated that the tornado reached F3 strength.
After passing just northwest of Clatonia, the tornado became violent and moved through Hallam at 8:35 pm CDT, where damage reached high-end F4 in intensity. At Hallam, the tornado was a record-breaking wide, making it the widest tornado ever recorded at the time. Most houses in Hallam were completely demolished, along with farming equipment and other structures. A coal train was tossed off its tracks on the west side of town. Hallam escaped the most intense winds of the storm though, which were to the south. East of Hallam, damage was rated F2-F3 as the tornado turned east and began to cycle with a new circulation forming within the storm to the south of the tornado. It decreased in size to about as it passed north of Cortland, where it turned northeast and passed north of Firth. Norris School District 160 suffered severe damage, with the middle school being hit the worst. The auditorium roof and other walls within the school caved in. Buses were tossed and homes northeast of the school were flattened.
The tornado then reached F4 intensity again as it continued northeast to Holland before weakening again as it passed north-northwest of Panama, where mostly F1 and F2 damage was observed. The tornado then tracked north-northeast to Bennet, where some houses received F3 damage. At Bennet, the tornado turned east-northeast and began to thin out. Damage east-northeast of Bennet was in the F0-F1 range. The tornado finally dissipated a mile west-southwest of Palmyra at 9:10 pm CDT.[2]
The storm was long-lived, having been on the ground for more than 100 minutes. It was also a long-track tornado, having covered .[3] Even though it damaged towns and demolished many buildings, there were no damage-cost estimates available. The Hallam tornado became the widest on record until it was surpassed on May 31, 2013, by the El Reno, Oklahoma tornado, which had a width of .[4] Its width has since also been tied by the 2016 Jiangsu tornado.[5] [6] However, the Hallam tornado still holds the record for the largest condensation funnel recorded.[7]