Flood — Grant, South Dakota

2023-04-11 to 2023-04-16 · near Hiland, Grant, South Dakota

Event narrative

Big Sioux river near Florence peaked in major flood stage at 9.58 feet in the early morning hours of April 13th. This is a record flood stage for this location. Being the headwaters of the Big Sioux the main impacts were to local and county roads and bridges as well as agricultural lands.

Wider weather episode

The combination of a deep snowpack, a liquid equivalent exceeding 4 inches, and frozen soils due to persistently below-normal spring temperatures set the stage for flooding along the Big Sioux. However, a significant rise in temperatures, well above normal, triggered rapid snowmelt. The resulting runoff swiftly made its way into the Big Sioux River and its associated tributaries.

The Big Sioux river headwaters near Florence set a record flood stage. Points downstream along the Big Sioux River crested at moderate to major flood stage. Many local and county roads and bridges were impacted by the high water, along with widespread inundation of agricultural lands.

A Presidential Disaster Declaration was approved for Brown, Clark, Codington, Day, Faulk, Grant, Hand, Marshall, Potter and Roberts Counties, as well as for the Lake Traverse Indian Reservation, where an estimated $2,305,362 in total qualifying costs were incurred during spring flooding.

Apart from the mainstem river, there was heightened concern regarding Lake Kampeska. The Watertown Water Filtration plant and numerous local residences faced threats from both elevated lake water levels and the potential for ice breakup and shoves. In response, residents initiated sandbagging operations to safeguard their properties.

View location on OpenStreetMap → (45.2600, -97.2200)

Source: NOAA Storm Events Database, event_id 1089080. Narrative written by the NWS forecast office that issued the report.