Walworth County, South Dakota: hazard history

FEMA declared 12 disasters that named Walworth County between 1976 and 2020.

Most recent declarations

• DR-4527 2020 · Biological · Covid-19 Pandemic
• EM-3475 2020 · Biological · Covid-19
• DR-4463 2019 · Flood · Severe Storms And Flooding
• DR-4440 2019 · Flood · Severe Winter Storm, Snowstorm, And Flooding
• DR-1887 2010 · Severe Storm · Severe Winter Storm
• EM-3234 2005 · Coastal Storm · Hurricane Katrina Evacuation
• DR-1173 1997 · Flood · Severe Flooding, Sever Winter Storms,heavy Rains High Winds
• DR-1156 1997 · Severe Storm · Severe Winter Storms And Blizzard Conditions
• DR-1052 1995 · Flood · Flooding
• DR-1045 1995 · Snowstorm · Severe Winter Storms

Not counted above: 41 statewide declarations, which covered every county in South Dakota. A declaration is a decision to send federal help, not a measure of how bad an event was. Records run from 1953. Source: FEMA OpenFEMA Disaster Declarations Summaries.

Records start in 1996. Damage is NOAA's estimate at the time, in nominal dollars, and is often rounded; it is not insurance claims data. A storm that crossed two NOAA zones in this county is recorded, and counted, once per zone. A storm filed against a forecast zone is counted in every county that zone covers, with the whole storm's damage; do not add these figures across counties.

NOAA storm event records in Walworth County each year. The busiest year was 2012, with 39 records.

Years with no record are left out of the table, not shown as zero.

Costliest records

1. Flash Flood · May 17, 2018$3.0M
   NOAA name: Walworth County · NOAA record 759648
2. Flood · Apr 1, 2019$292K
   NOAA name: Walworth County · NOAA record 819580

Deadliest records

1. Ice Storm · Dec 25, 20161 death
   NOAA name: NWS forecast zone · NOAA record 670231
2. Extreme Cold/Wind Chill · Jan 8, 20191 death
   NOAA name: NWS forecast zone · NOAA record 804570

Each line is one NOAA record, linked to its page at NOAA. One large storm can appear more than once if NOAA recorded it in several zones of this county. Dollars are nominal.

No National Flood Insurance Program claims are on record for Walworth County.

A count of claims, not a rate: NFIP publishes no count of insured homes beside it, and most flood damage is uninsured. Nominal dollars. Records run from 1978 to 2024; claims filed without a county code are not on any county page. Source: FEMA OpenFEMA FIMA NFIP Redacted Claims.

A hazard vulnerability analysis rates each hazard for probability, impact, preparedness and response. Probability is the one column the county’s federal record can fill — NCEI storm events from 1996 to 2026 and FEMA declarations naming the county — and this is what it says for a facility here, on the 0–3 scale of the all-hazards structure surveyors expect. The other six columns are the facility’s own judgment about its building, and Calchis leaves them blank.

A dash means the record does not speak to that hazard; it is not a zero. Whether a finished document satisfies the CMS Emergency Preparedness Rule is the facility’s finding and its surveyor’s. Complete the HVA for a facility in Walworth County — the technological, human and hazardous-materials rows, the six facility columns, the approval and the printed document — or read the sample analysis on that page first.

• Every figure is counted from public federal records held by Calchis: NOAA NCEI Storm Events, FEMA OpenFEMA Disaster Declarations, and FEMA NFIP claims. Nothing is modeled or estimated.
• NOAA files some events against a county and others against an NWS forecast zone, and publishes a code for both. Records are counted as Walworth County by that code — county records by the county's own FIPS code, zone records through the National Weather Service's published list of which counties each zone covers. No name matching is involved. Of 571 records, 322 were filed against this county and 249 against a forecast zone covering it. A zone storm is counted in every county its zone covers, and its damage figure is the whole storm's, not this county's share — NOAA does not publish that split. So these figures describe this county; they must not be added up across counties.
• Counts last rebuilt from the source records on Sep 15, 2026.
• This county's NOAA record is short (under 100 records, under 10 with damage, or under 10 years), so this page is not offered to search engines. It is still accurate.