(CNN) A storm that tore across Sioux Falls overnight was so treacherous, even weather forecasters had to pause their work and hunker down.

Now city officials say human error prevented some of the city's outdoor warning sirens from blaring like they should have.

The severe weather that struck South Dakota's largest city spawned at least one tornado, the National Weather Service said.

In Sioux Falls for 2 weeks and we get hit by a tornado. Wth pic.twitter.com/D37CEvAaLS — Zoety04 (@Zoety04) September 11, 2019

"Obviously we had widespread damage throughout the entire city," said Todd Heitkamp of the weather service's Sioux Falls office.

"Most of that damage was a result of probably 100-mph-plus winds. And some of the damage was a little bit more intense, and we're suspecting that was a result of some brief, spin-up tornadoes."

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