South Dakota state officials closed Interstate 29 in southeast South Dakota at noon today, Central time.

The Big Sioux River is predicted to crest in the morning or early afternoon hours of Friday, June 20 and is expected to send a significant amount of water into low lying areas of southeast South Dakota.

A berm, or levee, is being built across both lanes of interstate 29 at Exit 4. That protective structure will connect with an existing levee on the east side of North Sioux City.

Through traffic on Interstate 29 will be detoured as follows:                      

  • Southbound I-29 Interstate traffic will be detoured onto I-90 east at Exit 84A at Sioux Falls, S.D., then south on I-35 Exit 159A at Des Moines, Iowa, then west on I-80 at Exit 137A to Council Bluffs, Iowa, then to I-29 south.
  • Northbound I-29 Interstate traffic will be detoured at Council Bluffs, Iowa onto I-80 eastbound, then north on I-35 in Iowa to Albert Lea, Minn., and west on I-90 to Sioux Falls, S.D.

Interstate through traffic detour on local roads:

  • Southbound I-29 traffic in South Dakota will be detoured onto state route 50 West at Exit 26 to Vermillion, then south to SD 19 into Nebraska where it becomes Highway 15, then continue south to Highway 12 east in Nebraska to U.S. 20 east in Nebraska, then to Exit 1A for I-29 south at South Sioux City, NE.
  • Northbound I-29 traffic will exit onto Highway 20 west, then north on Highway 12 and Highway 15 in Nebraska, continuing onto Highway 19 in South Dakota to the Vermillion Exit to SD 50 eastbound to I-29.

As of mid-day Thursday, local traffic was being allowed into the area until water is over the road.

Detour maps are available on the South Dakota state website.