NWS Sioux Falls confirms 10 tornadoes hit northwestern Iowa in historic December storm

Annie Todd, Sioux Falls Argus Leader
·3 min read
Tornado damage in Aurelia, South Dakota.
Tornado damage in Aurelia, South Dakota.

At least 10 tornadoes touched down in northwest Iowa and resulted in damage to trees, powerlines and various structures during a rare December storm system on Dec. 15, according to the National Weather Service.

"It is truly historic in every meaning of the word," said Peter Rogers, a warning coordination meteorologist for the NWS Sioux Falls office. "This just hasn't happened before in modern recorded history."

Since 1950, there have only been five recorded tornadoes in Iowa during December, Rogers said. Those tornadoes were only concentrated in the southern and eastern part of the state.

The storm was so rare that it was the first time since record keeping began in 1986 that a severe thunderstorm and tornado warning had to be issued in December by the NWS Sioux Falls Office.

Confirmed tornadoes that occured on Dec. 15 during a severe storm that impacted southeastern South Dakota and northwestern Iowa.
Confirmed tornadoes that occured on Dec. 15 during a severe storm that impacted southeastern South Dakota and northwestern Iowa.

A complex Derecho storm

A Derecho storm usually involves a large area of thunderstorms that moves quickly and has straight-line wind gusts of at least 60 miles per hour, Rogers explained.

But the storm-system that moved through Nebraska, southeastern South Dakota and northwestern Iowa was a complex Derecho because of the embedded tornadoes and high wind gusts, Rogers said.

"In this case we had both, which made the whole system more complex and difficult to work with," he said.

As of Wednesday, the NWS has confirmed 78 tornadoes touched down in Nebraska, Iowa, Minnesota and Wisconsin.

Tornado damage in Sergeant Bluff, Iowa.
Tornado damage in Sergeant Bluff, Iowa.

Tornado damage recorded in storm area

The NWS Sioux Falls office issued summary reports for all 10 tornadoes. The NWS said there were no injuries. Here's a synopsis of all of them:

Aurelia between Cherokee and Buena Vista County:

  • A grain elevator damaged, three empty rail cars tipped and power poles knocked loose near Main Street and 560th Street. A barn and three outbuildings destroyed along 535th Street. Multiple trees and power poles damaged. (EF Rating: EF-1)

Sergeant Bluff in Woodbury County:

  • Machine shed destroyed and several outbuildings and four farmsteads damaged between 230th Street and 240th Street. (EF Rating: EF-1)

Lawton in Woodbury County:

  • Roof damaged at a single-family home near 190th Street northeast of Bronson. Hit two metal utility transmission towers, impacted multiple farmsteads and destroyed a machine shed. Multiple power poles and trees damaged. (EF Rating: EF-2)

Kingsley between Woodbury and Plymouth County:

  • Two barn roofs destroyed as well as an outbuilding, a collapsed garage and damage to multiple farmsteads. (EF Rating: EF-1)

Battle Creak in Ida County:

  • A home lost shingles, four farmsteads impacted with outbuildings damaged or destroyed. (EF Rating: EF-1)

Alta between Ida, Cherokee and Buena Vista County:

  • Four farmsteads damaged and damage to a home north of Galva. Multiple trees impacted or uprooted. (EF Rating: EF-1)

Rembrandt in Buena Vista County:

  • Two farmsteads had damage to outbuildings. Power poles damaged resulting in power outages. (EF Rating: EF-2)

Milford in Dickinson County:

  • Power poles damaged and a part of a roof lifted from a home. (EF Rating: EF-1)

Larrabee between Cherokee and O'Brien County:

  • Destroyed a machine shed, chicken barn and four silos. An outbuilding was also destroyed. Multiple trees damaged. (EF Rating: EF-1)

Salix in Woodbury County:

  • No damage recorded (EF Rating: EF-Unknown)

A learning event

While these kinds of storms can be expected in South Dakota and Iowa during the late spring and early fall, this storm was rare.

Because of the rarity of the event, Rogers says the NWS will be learning from the storm for a while.

More: South Dakota counties removed from tornado watch as storms move through

"This is going to be a system that's probably studied for many, many years and I'm sure there's going to be a lot of lessons learned and things that we take away from it so that we can continue to improve our products and services moving forward," he said.

Follow Annie Todd on Twitter @AnnieTodd96. Reach out to her with tips, questions and other community news at atodd@argusleader.com or give her a call at 605-215-3757.

This article originally appeared on Sioux Falls Argus Leader: 10 tornadoes hit Iowa amid December derecho, storm