FEMA Records
12
Low volume
South Dakota · FEMA + NOAA + National Risk Index
Walworth County, SD
12 FEMA disaster declarations (1976-2020), with a FEMA National Risk Index rating of Very Low. Most common hazard: Flood.
- 12
- FEMA declarations
- 9
- Major disasters
- 40
- NRI risk · Very Low
- Flood
- Top hazard
The verdict
Walworth County has a nationally busy FEMA history: 12 declarations, more than 14% of counties in this registry. But the state comparison tempers that reading: the total is 37% below the South Dakota county mean. FEMA's separate National Risk Index places the county safer than 40%; that score models loss and vulnerability rather than counting declarations.
- Safer than 40%
- of U.S. counties for FEMA National Risk Index score
- Very Low
- FEMA National Risk Index rating
- 12
- FEMA declarations vs 21 national county avg
- 5
- flood declarations, the most common hazard here
FEMA's National Risk Index and its declaration registry are separate measures. This county's registry includes Major Disaster (DR) and Emergency (EM) records; an EM authorizes a narrower set of federal assistance than a DR.
How does Walworth County compare?
Walworth County vs. all counties in this dataset
FEMA disaster declarations, all-time
12 14th percentile higher than 14% of 3,266 counties
Each bar is a band; taller bars hold more counties. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source FEMA Disaster Declarations Summaries v2 · 2026-08-03
Walworth County's FEMA Risk Index score
FEMA National Risk Index composite score vs. the South Dakota county average
What does Walworth County's hazard record show?
FEMA National Risk Index
FEMA's data shows an elevated National Risk Index composite of 39.5/100 for this county (Very Low rating). Expected Annual Loss comes in at Very Low (roughly $10.2M in annualized losses). Social vulnerability (Relatively High) and community resilience (Very High) both factor into how that raw exposure plays out on the ground. Among the 18 modeled hazards, Cold Wave carries the county's highest rating, a mid-range Relatively Moderate. FEMA's modeled frequency puts that hazard at an average of 11 times per year here, based on 212 historical events on record.
Declaration frequency
Nationally, Walworth County's 12 FEMA records form a high-volume history; within South Dakota, however, the count is 37% below the county mean. 9 entries carry the Major Disaster classification. The largest incident group is Flood, appearing 5 times. The full 44-year record averages 0.3 declarations annually. A DR label alone does not say whether Individual Assistance, Public Assistance, or both followed.
Reading the federal records together
No paid-claim row for this county appears in the NFIP county table used by PlainHazard. That absence is not evidence that flooding never occurred: the register observes claims under federal flood-insurance policies, not uninsured losses, emergency reports, or every flood outside the program. The FEMA declaration history below is therefore the available federal-action record on this page.
Start with the state benchmark: a South Dakota county averages 19.0 federal declaration records, while Walworth County has 12. The gap is 37% below that mean. Fewer entries indicate a quieter history of recorded federal actions, not immunity from a hazard and not a prediction about what happens next.
51 /100
Historical Activity Index
High historical activity
Walworth County, SD · PlainHazard-derived composite from federal records
This 0–100 index is an explicit PlainHazard composite from FEMA declaration history only on the county surface (this DB has no county-level NOAA damage row) . It is not FEMA's National Risk Index, not a forecast, and not a safety, insurance, or preparedness rating. Open the calculator · Methodology
FEMA Declarations (1953–present) Moderate
9/30
12 OpenFEMA declarations, full ingest window (0.6x national county average)
County Disaster Density Moderate
8/25
12 declarations (0.6x state county average of 19)
Major Disaster Share Very High
19/25
9 of 12 declarations are major disasters (75%)
Hazard Diversity Very High
15/20
6 different disaster types declared in Walworth County
Historical Declaration Activity
Activity Band
High
vs. South Dakota Avg
-37%
State avg: 19.0
vs. National Avg
-42%
National avg: 20.7
Avg Per Year
0.3
Over 44 years
FEMA NRI 8-hazard radar - Walworth County
How to read this radar
Each axis: NRI risk rating (Very Low-Very High) on a 0-100 scale. Rounder = broad exposure; spiky = one or two hazards dominate.
Major Disaster share
75%
Mostly major
NRI risk score
40
Very Low
Source: FEMA National Risk Index Per-county per-hazard ratings, December 2025 release
How often does each hazard strike Walworth County?
FEMA's National Risk Index models a historical event count and an annualized frequency for each hazard type. Most hazards are expressed as modeled occurrences per year; FEMA expresses drought and heat-wave frequency as event-days per year. These modeled frequencies are not forecasts.
| Hazard | NRI Risk Rating | Recurrence |
|---|---|---|
| Cold Wave | Relatively Moderate | an average of 11 times per year |
| Winter Weather | Relatively Moderate | an average of 18 times per year |
| Wildfire | Relatively Low | roughly once every 742 years |
| Hail | Relatively Low | an average of 3.2 times per year |
| Drought | Relatively Low | 21 modeled event-days per year |
| Riverine Flooding | Very Low | roughly once every 2 years |
| Tornado | Relatively Low | roughly once every 4 years |
| Ice Storm | Very Low | roughly once every 2 years |
| Strong Wind | Relatively Low | an average of 2.2 times per year |
| Heat Wave | Very Low | 2.7 modeled event-days per year |
| Lightning | Very Low | an average of 32 times per year |
| Earthquake | Very Low | roughly once every 4,132 years |
| Landslide | Very Low | roughly once every 9 years |
Source: FEMA National Risk Index Modeled annualized frequency; drought and heat wave use event-days/year, December 2025 release
Disaster Types
Flood 5
Biological 2
Severe Storm 2
Coastal Storm 1
Snowstorm 1
Drought 1
What Flood declarations mean here
Flood is the most frequent declaration type on Walworth County's record, 42% of its declarations. Federal flood declarations cover two mechanisms that behave very differently: riverine flooding, which builds over days as a watershed drains and is usually forecast well in advance, and flash flooding, which can arrive in under an hour from rainfall that fell somewhere upstream.
Flood is also the one hazard class where a second federal dataset exists for the same events. The National Flood Insurance Program records what was actually paid on insured losses, so it measures a narrower thing than the declaration count: uninsured damage, and flooding outside mapped special flood hazard areas, never enters it. Reading the two together is more informative than either alone.
Declaration counts describe past federal action. They are a record of what was declared, not a forecast of future hazard probability.
Declaration Types
What DR / EM / FM mean
FEMA categorizes declarations as Major Disasters (DR), Emergencies (EM), or Fire Management Assistance (FM).
Major Disaster - 9 75.0%
of all 12 declarations
Emergency - 3 25.0%
of all 12 declarations
FEMA Declarations Timeline
| Year | Declarations | |
|---|---|---|
| 2020 | 2 | |
| 2019 | 2 | |
| 2010 | 1 | |
| 2005 | 1 | |
| 1997 | 2 | |
| 1995 | 2 | |
| 1986 | 1 | |
| 1976 | 1 | |
Disaster Declarations
How the 12 FEMA declarations break into federal action codes (DR / EM / FM). Same DISTINCT grain as the table below.
Download these 12 declarations as CSV . FEMA source data is public domain; our derived presentation is CC0.
| DR# | Title | Type | Incident | Date |
|---|---|---|---|---|
| 4527 | COVID-19 PANDEMIC | DR | Biological | 2020-04-05 |
| 3475 | COVID-19 | EM | Biological | 2020-03-13 |
| 4463 | SEVERE STORMS AND FLOODING | DR | Flood | 2019-09-23 |
| 4440 | SEVERE WINTER STORM, SNOWSTORM, AND FLOODING | DR | Flood | 2019-06-07 |
| 1887 | SEVERE WINTER STORM | DR | Severe Storm | 2010-03-10 |
| 3234 | HURRICANE KATRINA EVACUATION | EM | Coastal Storm | 2005-09-10 |
| 1173 | SEVERE FLOODING, SEVER WINTER STORMS,HEAVY RAINS HIGH WINDS | DR | Flood | 1997-04-07 |
| 1156 | SEVERE WINTER STORMS AND BLIZZARD CONDITIONS | DR | Severe Storm | 1997-01-10 |
| 1052 | FLOODING | DR | Flood | 1995-05-26 |
| 1045 | SEVERE WINTER STORMS | DR | Snowstorm | 1995-03-14 |
| 764 | SEVERE STORMS & FLOODING | DR | Flood | 1986-05-03 |
| 3015 | DROUGHT | EM | Drought | 1976-06-17 |
Storm Events in South Dakota
Statewide NOAA context only. PlainHazard does not currently attribute these state totals to Walworth County.
| Storm Type | Events | Fatalities | Injuries | Property Damage |
|---|---|---|---|---|
| Thunderstorm Wind | 5,388 | 7 | 21 | $10.7M |
| Hail | 4,801 | 0 | 3 | $4.5M |
| High Wind | 2,277 | 0 | 1 | $35.0K |
| Winter Weather | 2,125 | 20 | 50 | $133.0K |
| Flood | 1,523 | 5 | 0 | $196.2M |
Source: NOAA Storm Events Database State-level aggregated data, 2015-2025
FEMA National Risk Index
Overall Risk
Very Low
Score: 39.5/100
Expected Annual Loss
Very Low
$10.2M/year
Social Vulnerability
Relatively High
Community Resilience
Very High
Hazard Risk Breakdown
Cold Wave Relatively Moderate
Winter Weather Relatively Moderate
Wildfire Relatively Low
Hail Relatively Low
Drought Relatively Low
Riverine Flooding Very Low
Tornado Relatively Low
Ice Storm Very Low
Strong Wind Relatively Low
Heat Wave Very Low
Lightning Very Low
Earthquake Very Low
Landslide Very Low
Source: FEMA National Risk Index (NRI) Ratings reflect relative scores among all US counties. Data: hazards.fema.gov/nri
The model's sharpest exposure here: Cold Wave
Cold Wave measures exposure to extreme cold rather than to snow. Its harm is concentrated in health effects, burst infrastructure and energy demand spikes, and it falls hardest where the building stock and the grid were not built with sustained cold in mind.
Worth noting for Walworth County: the model and the federal record do NOT point at the same hazard. Cold Wave carries the highest modeled rating (Relatively Moderate), while the county's declaration history is led by Flood. That is not a contradiction, the two measure genuinely different things. Declarations record federal ACTION, which requires damage costly enough to exceed state and local capacity; the Risk Index models EXPECTED annual loss across all 18 hazards whether or not any declaration ever followed. A hazard can be the county's largest modeled exposure and never once have driven a declaration.
National Risk Index ratings are modeled estimates of expected annual loss, not predictions of what will happen in any given year.
Data-matched county comparisons
Walworth County's closest FEMA peer: Vermilion County, IL
Comparisons use published FEMA declaration fields plus the National Risk Index composite for Walworth County. Record similarity, not a safety rating.
Closest declaration profiles
Walworth County shows 12 FEMA declarations, led by Flood.
Similar Major-disaster share
Walworth County: 9 of 12 of its declarations are Major.
Similar modeled NRI score
Walworth County: NRI composite 39.5 (Very Low).
How these peers are chosen
Cohort: Published U.S. county equivalents outside the source state or territory. Each metric keeps six ETL candidates; three unique destinations are shown after de-duplicating across axes. Declaration-volume ranking combines count and Major-disaster share and prefers a different leading incident type; Major-share ranks the Major fraction adjusted for volume; NRI ranks the modeled composite score only.
Retained FEMA snapshot feed for Walworth County - capture-dated entries only.
Further reading for this county
Most disaster-prone counties
With 12 FEMA declarations, Walworth County sits in the high-volume declaration band - see how that count ranks against other U.S. counties.
More PlainHazard guides
- Most disaster-prone counties - U.S. counties ranked by FEMA declaration totals.
- Understanding disaster data - declarations vs storm events vs NRI scores.
- Preparing for natural disasters - household checklist (not county-specific advice).
Related
Frequently Asked Questions
What is the most common disaster type in Walworth County?
The most common disaster type in Walworth County is Flood, with 5 declarations. Other disaster types include Biological (2), Severe Storm (2), Coastal Storm (1).
How does Walworth County's FEMA declaration record compare with the South Dakota average?
The typical South Dakota county has 19.0 FEMA declaration records; Walworth County has 12, or 37% fewer. Against the national county mean of 20.7, this county's total is 42% lower. The comparison is historical and says nothing about the probability of a future event.
How many major FEMA disaster declarations has Walworth County received?
Walworth County has received 9 major disaster declarations, representing 75% of all 12 disaster declarations.
What was the worst year for disasters in Walworth County?
The most active year for disaster declarations in Walworth County was 1995, with 2 declarations. The county has FEMA disaster data spanning 1976 to 2020.
What is the FEMA National Risk Index score for Walworth County?
According to the FEMA National Risk Index, Walworth County, South Dakota has an overall risk score of 39.5 out of 100 (Very Low). The county's social vulnerability rating is Relatively High and community resilience is Very High. The Expected Annual Loss (EAL) score is Very Low, representing $10.2M in annualized losses.
Which natural hazard poses the greatest risk to Walworth County?
The top hazard flagged by FEMA's NRI for Walworth County as of the latest release is Cold Wave (risk rating: Relatively Moderate). Other significant hazards include Winter Weather (Relatively Moderate) and Wildfire (Relatively Low). FEMA's modeled event frequency puts cold wave here at an average of 11 times per year, drawn from 212 historical events on record. FEMA derives these ratings from historical event frequency, the assets exposed, and the community's vulnerability profile.
Data Sources & Methodology
Disaster declaration data comes from the FEMA OpenFEMA Disaster Declarations Summaries v2 API, which includes all federally declared disasters, emergencies, and fire management assistance grants.
Storm event data is sourced from the NOAA Storm Events Database (2015-2025), which tracks significant weather events including thunderstorms, tornadoes, floods, and winter storms.
This data is provided for informational purposes only. FEMA disaster declarations represent federal response actions and may not capture all local emergencies or weather events.
What this means for Walworth County
Against a South Dakota county mean of 19 declarations, Walworth County, SD records 12, or 37% fewer. PlainHazard classifies that historical total as high activity.
- Major Disaster is the largest group (9 of 12) in a declaration history that remains below its state benchmark; frequency here is not a forecast. South Dakota overview
- Nationally the county exceeds 14% of recorded county totals, but its own South Dakota benchmark is higher. The ranking keeps those two contexts separate. Most-disaster rankings
- With no NFIP county row, the declaration register and modeled NRI remain distinct evidence rather than substitutes for a claims history. Disaster-data guide
A below-average federal record is not a safety guarantee. Use National Weather Service alerts and local emergency-management notices for present conditions, not this historical comparison.
PlainHazard derives this profile from FEMA's Disaster Declarations Summaries and National Risk Index data. The declaration comparison covers 3,266 U.S. counties and county equivalents in this database, refreshed as of 2026-08-03. Read our methodology - how this data is sourced, computed, and verified.
All federal data sources used on this page
- FEMA OpenFEMA, Disaster Declarations Summaries v2 - all federally-declared disasters for this county. fema.gov/openfema/disaster-declarations
- FEMA National Risk Index (NRI) - per-county per-hazard risk ratings and expected annual loss. hazards.fema.gov/nri
- NOAA NCEI Storm Events Database - state-level storm/severe-weather event records, 2015-2025. ncdc.noaa.gov/stormevents
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainHazard Editorial
Verify with FEMA → · Verify with FEMA NRI → · Verify with NOAA →
Every figure on PlainHazard is rendered directly from FEMA federal disaster data, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or national statistics report, the data & editorial changelog, or report a data error.