Large late-night tornado, strong straight-line winds hit Sioux Falls, causing significant damage, South Dakota

A large, late-night tornado hit south and central Sioux Falls, South Dakota around 23:41 LT on Tuesday, September 10, 2019 (04:41 UTC, September 11), causing significant damage and power outages. Residents were asked to stay out of roads and call 911 only in emergencies.

Officials said they received numerous reports and photos of extensive damage to trees, cars, homes, and businesses around the city. In the wake of the storm, the Sioux Falls Police Department issued a 'No Travel Advisory' due to numerous downed power lines and trees in southeastern parts of the city.

According to authorities, 37 structures collapsed or have structural integrity issues due to tornadic activity and winds in excess of 160 km/h (100 mph).

As many as 25 000 customers were left without power.

Several people were injured, but there were not any reported fatalities or serious injuries, the Sioux Falls Argus Leader reported.

"Based on early assessments, the area of Sioux Falls that received the great impact from the overnight storm is bordered by 26th Street on the north, 85th Street on the south, Marion Road on the west and Minnesota Avenue on the east," Sioux Falls Fire Rescue said.

Meteorologist Todd Heitkamp of NWS Sioux Falls said first reports confirming a tornado started coming at 11:38 LT. The majority of the damage was caused by strong straight-line winds, he said.

For information on the latest road closures please see the map at https://t.co/DdMobLvtQ4 .@CitySiouxFalls .@siouxfallspd #WeAreSFFR /sf

— Sioux Falls Fire (@SiouxFallsFire) September 11, 2019

Mayor Paul TenHaken said there was a "breach of protocol" in the city's outdoor warning siren system. 

The mayor said that it appeared a majority of the sirens had sounded in the southwest of the city, where some of the most serious damage occurred. But that's not how the system is supposed to work — either every siren should be sounding or none of them.

"We're doing an internal investigation on why that happened, why the existing protocol was not followed," he said. "The city recognizes that, is owning that, and we'll be taking the proper steps to rectify that."

"Shortly after that weather passed through, the city of Sioux Falls went into action and set up our emergency operations center, we’ve been in there for about four hours doing the assessment of what has happened, what we’ve seen with the damage," TenHaken said early Wednesday morning. "This happened when it was dark and it’s still dark, so there’s still a lot that we don’t know until the sun comes up."

"There is significant damage throughout the city," TenHaken said. "We’ve heard of some large damage to places like Alvera Behavioral Health and the 41st and Western area appears to be an area that was hit particularly hard as well. We’re anxious for the sun to come up here so that we can get a better look at what we’re facing."

Here’s some more #storm #damage photos from #SiouxFalls, #SouthDakota after a nocturnal #tornado on 10 September 2019. #SDwx pic.twitter.com/50QIN5AuhJ

— Derek Thompson (@DerekjT1003) September 11, 2019

Advance Auto Parts on 41st. pic.twitter.com/mhy7d6G1LA

— Abigail Dollins (@abigaildollins) September 11, 2019

Debris in the road on 41st. pic.twitter.com/d0ioeomzq8

— Abigail Dollins (@abigaildollins) September 11, 2019

Firefighters work to clean up trees down across the roads near W. 33rd Street. pic.twitter.com/lOJ6EIcotZ

— Abigail Dollins (@abigaildollins) September 11, 2019

A car flipped on its side in a parking lot near 41st. pic.twitter.com/shHjlTYbzc

— Abigail Dollins (@abigaildollins) September 11, 2019

A better look at some of the damage from the tornado that went through Sioux Falls late Tuesday evening. pic.twitter.com/fny3djB0Sj

— Abigail Dollins (@abigaildollins) September 11, 2019

A power line snapped and trees down on S. Grange Ave. pic.twitter.com/aj2wg1rjeM

— Abigail Dollins (@abigaildollins) September 11, 2019

According to the Argus Leader, Sioux Falls isn't the only city to have its outdoor warning siren system fail in recent months. Similar failures occurred this year in other U.S. cities, including Belton, Missouri, Cleveland, Ohio, Daytona, Florida and Oklahoma City, Oklahoma.

Featured image credit: NOAA/GOES-East. Acquired: 04:10 UTC on September 11, 2019