BISMARCK – Less than 48 hours after the lives of two people were lost in Tuesday morning’s flash flooding in Sioux County, many unanswered questions remain.
“Real true flash flooding is fairly rare in North Dakota, we just don’t often get high rainfall rates over a very short period of time,” said Bill Abeling with the Bismarck National Weather Service.
But that is exactly what happened in Southern Sioux County Monday Night through Tuesday morning, in some spots, over 7 inches of rain fell…overwhelming the regions topography leading to the washout of Kenel Road.
KX News sat down with the National Weather Service and they tell us this was an exceptionally rare event.
“The rainfall rates that we were seeing from some of our programs indicated that we were getting 200-500 year flows within some of these basins,” said Abeling
One of those basins included Joe Bush Creek that traveled underneath Kenel Road. Abeling tells KX News the culvert was no match because of how fast the creek was flowing…
“The type of water that was flowing here was flowing at 10, 20, 30 miles an hour. And at that rate, it will quickly, if it comes up against an area of dirt, all it has to do it start eroding a small section, and it can very quickly demolish an area,” said Abeling
He adds in his 35 years, he’s never seen destruction like this from flash flooding…
“Not in North Dakota, I haven’t seen it erode this big of a hole, I’ve seen dams overtopped, in which case there’s severe erosion from that but this is the worst road erosion I’ve seen,” said Abeling
But there are still many unknowns, such as how often is that culvert inspected? and who’s ultimately responsible for maintaining that section of road. KX News placed calls to the Standing Rock Tribe as well as Sioux County officials and have not received a response yet.