Flood Zones in Turner County, SD: Vermillion River Risk

Turner County's June 2024 flood event on the West Fork Vermillion River near Parker wasn't a one-off. The South Dakota Flood Information System maintains named monitoring locations for both the West and East Fork Vermillion at Parker, and modeled flood-risk data puts a real number on county-wide exposure -- about 1 in 10 properties countywide. Here's what that means for a specific parcel, and where to check it directly.

This page covers what's specific to Turner County. For the general explanation, see the national guide.

Two named, monitored flood locations converge at Parker

The Vermillion River itself is formed by the confluence of its East Fork and West Fork in Parker Township, right at Turner County's county seat -- which is exactly why the county carries real, mapped flood exposure rather than a generic statewide disclosure. The South Dakota Flood Information System (SDFIS), the state's dedicated flood-forecasting and mapping platform, maintains specifically named monitoring and inundation-mapping locations for "Parker, East Fork" and "Parker, West Fork," alongside real-time stream conditions and flood forecasts. That's a genuinely local, checkable resource -- not just a pointer to a national flood map -- and it's the first place to look for current conditions or historical inundation extent for a parcel near either fork.

That local monitoring exists because the risk is real and recent: in June 2024, the National Weather Service issued a flood warning for the West Fork Vermillion River near Parker as part of a broader southeastern South Dakota flood event, with Turner County reporting flooded roads and leaking buildings at the time. A buyer evaluating land near either fork, or near any of the county's smaller drainages, should treat the SDFIS mapped locations and the June 2024 event as a starting point for asking specific questions -- not as evidence that risk is confined to those two named spots, since the underlying drainage network extends well beyond the two gauge locations SDFIS names.

What the numbers say about county-wide exposure -- and what they don't

Modeled flood-risk data from First Street Foundation's Flood Factor puts a specific figure on Turner County's exposure: 866 properties, representing about 10% of all properties countywide, face greater than a 26% chance of being severely affected by flooding over the next 30 years, with 82 properties currently benefiting from some form of flood adaptation. That 10% figure is a genuinely useful screening number for evaluating how exposed Turner County is relative to a county with negligible flood risk -- but it's a county-wide modeled estimate, not a parcel-specific determination, and it should not be read as saying any given 1-in-10 property is the one at risk. Flood Factor's methodology differs from FEMA's official Special Flood Hazard Area designation, so a property flagged by one may not be flagged by the other, and vice versa.

For an actual purchase decision, the authoritative source is still a FEMA Flood Insurance Rate Map (FIRM) lookup for the specific parcel through the FEMA Flood Map Service Center, cross-checked against SDFIS's Parker-area gauge data and the county's own record of any past flood-related permit or drainage complaint. We were not able to confirm Turner County's specific NFIP community number or its current National Flood Insurance Program participation status through available sources -- that determines whether federally backed flood insurance is even available for a given property, and it's a real, unresolved question worth confirming directly with FEMA's Community Status Book or the Turner County Planning & Zoning Department before assuming either way.

Flood Zones in Turner County, South Dakota

Two named, monitored flood locations converge at Parker

What the numbers say about county-wide exposure -- and what they don't

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