FEMA Records
16
Below median
South Dakota · FEMA + NOAA + National Risk Index
Corson County, SD
16 FEMA disaster declarations (1976-2020), with a FEMA National Risk Index rating of Very Low. Most common hazard: Severe Storm.
- 16
- FEMA declarations
- 13
- Major disasters
- 38
- NRI risk · Very Low
- Severe Storm
- Top hazard
The verdict
Corson County has a nationally busy FEMA history: 16 declarations, more than 27% of counties in this registry. But the state comparison tempers that reading: the total is 16% below the South Dakota county mean. FEMA's separate National Risk Index places the county safer than 38%; that score models loss and vulnerability rather than counting declarations.
- Safer than 38%
- of U.S. counties for FEMA National Risk Index score
- Very Low
- FEMA National Risk Index rating
- 16
- FEMA declarations vs 21 national county avg
- 1
- NFIP flood insurance claims filed
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 Corson County compare?
Corson County vs. all counties in this dataset
FEMA disaster declarations, all-time
16 27th percentile higher than 27% 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
Corson County's FEMA Risk Index score
FEMA National Risk Index composite score vs. the South Dakota county average
What does Corson County's hazard record show?
FEMA National Risk Index
FEMA's data shows an elevated National Risk Index composite of 38.1/100 for this county (Very Low rating). Expected Annual Loss comes in at Very Low (roughly $7.1M in annualized losses). Social vulnerability (Very High) and community resilience (Very Low) both factor into how that raw exposure plays out on the ground. Of the 18 hazards FEMA models, Cold Wave stands out as the sharpest exposure here, rated Relatively High. FEMA's modeled frequency puts that hazard at an average of 10 times per year here, based on 192 historical events on record.
Declaration frequency
Nationally, Corson County's 16 FEMA records form a high-volume history; within South Dakota, however, the count is 16% below the county mean. 13 entries carry the Major Disaster classification. The largest incident group is Severe Storm, appearing 8 times. The full 44-year record averages 0.4 declarations annually. A DR label alone does not say whether Individual Assistance, Public Assistance, or both followed.
Reading the federal records together
This county has a small entry in FEMA's NFIP paid-claims table: 1 claim and $450 paid in total. PlainHazard calls 1-49 claims a light registry record, a label for this dataset rather than a finding that flood exposure is low. A short claims history can also reflect insurance take-up, the period covered, or losses that were never insured.
Start with the state benchmark: a South Dakota county averages 19.0 federal declaration records, while Corson County has 16. The gap is 16% 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.
58 /100
Historical Activity Index
High historical activity
Corson 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
12/30
16 OpenFEMA declarations, full ingest window (0.8x national county average)
County Disaster Density Moderate
11/25
16 declarations (0.8x state county average of 19)
Major Disaster Share Very High
20/25
13 of 16 declarations are major disasters (81%)
Hazard Diversity Very High
15/20
6 different disaster types declared in Corson County
Historical Declaration Activity
Activity Band
High
vs. South Dakota Avg
-16%
State avg: 19.0
vs. National Avg
-23%
National avg: 20.7
Avg Per Year
0.4
Over 44 years
FEMA NRI 8-hazard radar - Corson 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
81%
Mostly major
NRI risk score
38
Very Low
Source: FEMA National Risk Index Per-county per-hazard ratings, December 2025 release
How often does each hazard strike Corson 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 High | an average of 10 times per year |
| Wildfire | Relatively Low | roughly once every 794 years |
| Winter Weather | Relatively Moderate | an average of 17 times per year |
| Hail | Relatively Low | an average of 2.7 times per year |
| Ice Storm | Relatively Low | roughly once every 2 years |
| Strong Wind | Relatively Low | an average of 2 times per year |
| Drought | Very Low | 33 modeled event-days per year |
| Tornado | Very Low | roughly once every 2 years |
| Landslide | Very Low | roughly once every 1 years |
| Heat Wave | Very Low | 2.4 modeled event-days per year |
| Riverine Flooding | Very Low | an average of 1.7 times per year |
| Lightning | Very Low | an average of 32 times per year |
| Earthquake | Very Low | roughly once every 5,714 years |
Source: FEMA National Risk Index Modeled annualized frequency; drought and heat wave use event-days/year, December 2025 release
Disaster Types
Severe Storm 8
Biological 2
Flood 2
Snowstorm 2
Coastal Storm 1
Drought 1
What Severe Storm declarations mean here
Severe Storm is the most frequent declaration type on Corson County's record, 50% of its declarations. In FEMA's vocabulary this covers convective weather: thunderstorm straight-line winds, large hail, and the multi-day outbreaks that often carry embedded tornadoes. Activity is heaviest in spring and summer, though the season varies by region.
These events behave differently from a hurricane on paper. Damage tends to be distributed along a storm track rather than concentrated on a coastline, and a declaration typically follows an outbreak that crossed several counties over a few days, not a single point of impact. Because the qualifying threshold is the cost of uninsured public and individual losses rather than storm intensity, two similar storms can produce a declaration in one year and none in another.
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 - 13 81.3%
of all 16 declarations
Emergency - 3 18.8%
of all 16 declarations
FEMA Declarations Timeline
| Year | Declarations | |
|---|---|---|
| 2020 | 2 | |
| 2014 | 2 | |
| 2013 | 1 | |
| 2010 | 2 | |
| 2009 | 2 | |
| 2005 | 2 | |
| 1997 | 2 | |
| 1995 | 1 | |
| 1993 | 1 | |
| 1976 | 1 | |
Disaster Declarations
How the 16 FEMA declarations break into federal action codes (DR / EM / FM). Same DISTINCT grain as the table below.
Download these 16 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 |
| 4186 | SEVERE STORMS, TORNADOES, AND FLOODING | DR | Flood | 2014-07-28 |
| 4155 | SEVERE WINTER STORM, SNOWSTORM, AND FLOODING | DR | Severe Storm | 2013-11-08 |
| 4125 | SEVERE STORMS, TORNADO, AND FLOODING | DR | Severe Storm | 2013-06-28 |
| 1914 | SEVERE WINTER STORM | DR | Severe Storm | 2010-05-13 |
| 1887 | SEVERE WINTER STORM | DR | Severe Storm | 2010-03-10 |
| 1844 | SEVERE STORMS AND FLOODING | DR | Severe Storm | 2009-06-16 |
| 1811 | SEVERE WINTER STORM AND RECORD AND NEAR RECORD SNOW | DR | Snowstorm | 2008-12-12 |
| 3234 | HURRICANE KATRINA EVACUATION | EM | Coastal Storm | 2005-09-10 |
| 1596 | SEVERE STORM | DR | Severe Storm | 2005-07-22 |
| 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 |
| 1045 | SEVERE WINTER STORMS | DR | Snowstorm | 1995-03-14 |
| 999 | SEVERE STORMS, TORNADOES & FLOODING | DR | Severe Storm | 1993-07-19 |
| 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 Corson 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
NFIP Flood Insurance Claims
Total Claims
1
Total Paid
$450
Avg Per Claim
$450
Source: FEMA National Flood Insurance Program (NFIP) OpenFEMA Claims Data
FEMA National Risk Index
Overall Risk
Very Low
Score: 38.1/100
Expected Annual Loss
Very Low
$7.1M/year
Social Vulnerability
Very High
Community Resilience
Very Low
Hazard Risk Breakdown
Cold Wave Relatively High
Wildfire Relatively Low
Winter Weather Relatively Moderate
Hail Relatively Low
Ice Storm Relatively Low
Strong Wind Relatively Low
Drought Very Low
Tornado Very Low
Landslide Very Low
Heat Wave Very Low
Riverine Flooding Very Low
Lightning Very Low
Earthquake 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 Corson County: the model and the federal record do NOT point at the same hazard. Cold Wave carries the highest modeled rating (Relatively High), while the county's declaration history is led by Severe Storm. 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
Corson County's closest FEMA peer: Dakota County, NE
Comparisons use published FEMA declaration fields plus the National Risk Index composite for Corson County. Record similarity, not a safety rating.
Closest declaration profiles
Corson County shows 16 FEMA declarations, led by Severe Storm.
Similar Major-disaster share
Corson County: 13 of 16 of its declarations are Major.
Similar modeled NRI score
Corson County: NRI composite 38.1 (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 Corson County - capture-dated entries only.
Further reading for this county
Most disaster-prone counties
With 16 FEMA declarations, Corson 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 Corson County?
The most common disaster type in Corson County is Severe Storm, with 8 declarations. Other disaster types include Biological (2), Flood (2), Snowstorm (2).
How does Corson County's FEMA declaration record compare with the South Dakota average?
The typical South Dakota county has 19.0 FEMA declaration records; Corson County has 16, or 16% fewer. Against the national county mean of 20.7, this county's total is 23% lower. The comparison is historical and says nothing about the probability of a future event.
How many major FEMA disaster declarations has Corson County received?
Corson County has received 13 major disaster declarations, representing 81% of all 16 disaster declarations.
How many flood insurance claims has Corson County filed?
Corson County has 1 National Flood Insurance Program (NFIP) claims totaling $450 in payments, with an average of $450 per claim.
What was the worst year for disasters in Corson County?
The most active year for disaster declarations in Corson County was 1997, with 2 declarations. The county has FEMA disaster data spanning 1976 to 2020.
What is the FEMA National Risk Index score for Corson County?
According to the FEMA National Risk Index, Corson County, South Dakota has an overall risk score of 38.1 out of 100 (Very Low). Social vulnerability here rates Very High, while community resilience comes in at Very Low. The Expected Annual Loss (EAL) score is Very Low, representing $7.1M in annualized losses.
Which natural hazard poses the greatest risk to Corson County?
FEMA's NRI data points to Corson County as of the latest release is Cold Wave (risk rating: Relatively High). Other significant hazards include Wildfire (Relatively Low) and Winter Weather (Relatively Moderate). FEMA's modeled event frequency puts cold wave here at an average of 10 times per year, drawn from 192 historical events on record. These scores are based on FEMA's analysis of historical event frequency, exposed assets, and community vulnerability.
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.
Flood insurance data comes from the FEMA National Flood Insurance Program (NFIP) OpenFEMA claims dataset.
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 Corson County
Against a South Dakota county mean of 19 declarations, Corson County, SD records 16, or 16% fewer. PlainHazard classifies that historical total as high activity.
- Major Disaster is the largest group (13 of 16) in a declaration history that remains below its state benchmark; frequency here is not a forecast. South Dakota overview
- Nationally the county exceeds 27% of recorded county totals, but its own South Dakota benchmark is higher. The ranking keeps those two contexts separate. Most-disaster rankings
- A short NFIP claims file cannot establish low flood exposure; the data guide explains the limits of each federal measure. 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.