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(WGHP) — After multiple tornadoes devastated the middle of the US over the weekend, many people are wondering how they formed and why they were so intense.

A highly-amplified jet stream brought very active weather, according to FOX8 Meteorologist Charles Ewing.

On the cold side of the storm, snow fell from Nebraska to Michigan. On the warm side, powerful thunderstorms and tornadoes swept from Arkansas to Kentucky. 

Tornadoes also hit Illinois, Ohio, and Mississippi. The National Weather Service confirmed on Sunday that six tornadoes touched down across Tennessee on Saturday.

The first part of the severe weather outbreak was the jet stream carving a deep trough across the middle of the US, which helped to pull warm, humid air north. 

Strong winds then created wind shear within the jet stream. 

This means the winds were increasing quickly higher in the atmosphere. So, as the cold front moved across the middle of the country, the air was forced to rise, creating showers and thunderstorms. 

The storms were able to tap into the wind shear, and tornadoes were the result. 

It is unusual for a tornado to remain on the ground for an extended period. But under certain conditions, tornadoes can remain on the ground for many miles.

The Piedmont was able to avoid the power of this system because the strong jet stream winds moved into the northeast and Canada. 

  • Dog owner Derrick Starks, left, Chris Buchanan, center and Niki Thompson, right, both from neighboring counties, attempt to rescue Cheyenne from a tornado-damaged home in Mayfield, Ky., on Saturday, Dec. 11, 2021. Tornadoes and severe weather caused catastrophic damage across multiple states late Friday, killing dozens of people overnight. (AP Photo/Mark Humphrey)
  • A family digs through the remains of their apartment in Mayfield, Ky., Saturday, Dec. 11, 2021. Tornadoes and severe weather caused catastrophic damage across multiple states late Friday, killing several people overnight. (AP Photo/Timothy D. Easley)
  • Damaged vehicles and personal property are strewn over a wide area along Kentucky 81, Saturday, Dec. 11, 2021, in Bremen, Ky, after a devastating tornado swept through the area on Friday night. (Greg Eans/The Messenger-Inquirer via AP)
  • Matt Steele, right, digs through the remains of a house destroyed by a tornado in Bowling Green, Ky., Saturday, Dec. 11, 2021. (AP Photo/Michael Clubb)
  • In this photo taken by a drone, buildings are demolished in downtown Mayfield, Ky., on Saturday, Dec. 11, 2021, after a tornado traveled through the region Friday night. A monstrous tornado killed dozens of people in Kentucky and the toll was climbing Saturday after severe weather ripped through at least five states, leaving widespread devastation. (Ryan C. Hermens/Lexington Herald-Leader via AP)
  • In this aerial photo, a collapsed factory is seen with workers searching for survivors, Saturday, Dec. 11, 2021, in Mayfield, Ky., after tornadoes came through the area the previous night. (AP Photo/Gerald Herbert)
  • Emergency response workers dig through the rubble of the Mayfield Consumer Products candle factory in Mayfield, Ky., Saturday, Dec. 11, 2021. Tornadoes and severe weather caused catastrophic damage across multiple states late Friday, killing several people overnight. (AP Photo/Timothy D. Easley)
  • A workman uses an excavator to pile up the debris from a destroyed warehouse in Mayfield, Ky., Saturday, Dec. 11, 2021. Tornadoes and severe weather caused catastrophic damage across multiple states late Friday, killing dozens of people overnight. (AP Photo/Timothy D. Easley)
  • A fallen tree caused by a tornado takes down power lines and damages a car in Bowling Green, Ky., Saturday, Dec. 11, 2021. Storms swept through Bowling Green, Ky. near the Tennessee border, tearing roofs off homes and flinging debris into roadways. (AP Photo/Michael Clubb)
  • A car wrecked by a tornado sits on top of another car in Bowling Green, Ky., Saturday, Dec. 11, 2021. A monstrous tornado killed dozens of people in Kentucky and the toll was climbing Saturday after severe weather ripped through at least five states, leaving widespread devastation. (AP Photo/Michael Clubb)
  • A car sits in the debris caused by a tornado in Bowling Green, Ky., Saturday, Dec. 11, 2021. A monstrous tornado killed dozens of people in Kentucky and the toll was climbing Saturday after severe weather ripped through at least five states, leaving widespread devastation. (AP Photo/Michael Clubb)
  • Firefighters search a debris field that came from a house that was ripped off its foundation and trees were cut off after a tornado ripped along Highway F at the intersection of Stub Road in St. Charles County, Mo., on Friday, Dec. 10, 2021. A monstrous tornado, carving a track that could rival the longest on record, ripped through the middle of the U.S. in a stormfront that killed dozens and tore apart a candle factory, crushed a nursing home, derailed a train and smashed an Amazon warehouse. (David Carson/St. Louis Post-Dispatch via AP)

Rescuers are still combing through fields of wreckage after the tornado outbreak left dozens dead and communities in despair.

A twister carved a track that could rival the longest on record as the stormfront smashed apart a candle factory, crushed a nursing home and flattened an Amazon distribution center.

“I pray that there will be another rescue. I pray that there will be another one or two,” Kentucky Gov. Andy Beshear said, as crews sifted through the wreckage of the candle factory in Mayfield, where 110 people were working overnight Friday when the storm hit. Forty of them were rescued.

“We had to, at times, crawl over casualties to get to live victims,” said Jeremy Creason, the city’s fire chief and EMS director.

In Kentucky alone, 22 were confirmed dead by late Saturday, including 11 in and around Bowling Green. But Beshear said upwards of 70 may have been killed when a twister touched down for more than 200 miles (320 kilometers) in his state and that the number of deaths could eventually exceed 100 across 10 or more counties.

The death toll of 36 across five states includes six people in Illinois, where an Amazon facility was hit; four in Tennessee; two in Arkansas, where a nursing home was destroyed; and two in Missouri.

If early reports are confirmed, the twister “will likely go down perhaps as one of the longest track violent tornadoes in United States history,” said Victor Gensini, a researcher on extreme weather at Northern Illinois University.

The longest tornado on record, in March 1925, tracked for about 220 miles (355 kilometers) through Missouri, Illinois and Indiana. But Gensini said this twister may have touched down for nearly 250 miles (400 kilometers). The storm was all the more remarkable because it came in December, when normally colder weather limits tornadoes, he said.