Hanson County, South Dakota Natural Disaster Risk
FEMA National Risk Index assessment · SD
Very LowComposite Risk Score
National percentile: 15th
Hanson County faces very low composite natural disaster risk (NRI Risk Index score 14.8, 15th national percentile), driven primarily by drought and ice storm exposure. Expected annual loss across all 18 hazard types is $4M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Hanson County is very low, with a National Risk Index score of 14.8 out of 100 — placing it in the 15th national percentile and among the lowest-risk counties in the country. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Most of Hanson County's expected losses come from drought (extended dry periods that stress water supplies and agriculture) at Medium risk — $692K in expected annual loss and about 10.53 events per year; ice storm (freezing rain that coats surfaces in heavy, damaging ice) at Medium risk — $142K in expected annual loss and about 0.62 events per year; and hail (ice stones from severe thunderstorms that damage property and crops) at Low risk — $322K in expected annual loss and about 5.58 events per year. Across all hazards, FEMA estimates $4M in expected annual loss for a population of 3K.
Beyond physical exposure, Hanson County has a very high social vulnerability rating (how susceptible the population is to harm) and a very high community resilience rating (its capacity to prepare for and recover from disasters). Higher vulnerability is partly offset by strong community resilience and recovery capacity.
The county's disaster history tells the same story: Hanson County has received 25 federal disaster declarations since 1969, including 12 for flood events and 8 for severe storm events. The most recent was Severe Storms, Straight-Line Winds, and Flooding (flood), declared in August 2024.
Among 66 South Dakota counties, Hanson County ranks #39 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Drought | Medium | 10.53 / yr | $692K |
| Ice Storm | Medium | 0.62 / yr | $142K |
| Hail | Low | 5.58 / yr | $322K |
| Winter Weather | Low | 15.21 / yr | $62K |
| Wildfire | Very Low | 0.00 / yr | $44K |
| Cold Wave | Low | 7.89 / yr | $610K |
| Tornado | Low | 0.29 / yr | $710K |
| Landslide | Very Low | 0.05 / yr | $510 |
| Strong Wind | Low | 3.55 / yr | $303K |
| Heat Wave | Very Low | 5.95 / yr | $30K |
| Riverine Flood | Very Low | 2.21 / yr | $1M |
| Earthquake | Very Low | 0.00 / yr | $10K |
| Lightning | Very Low | 36.52 / yr | $23K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Hanson County has received 25 federal disaster declarations since 1969, most recently Severe Storms, Straight-Line Winds, and Flooding in August 2024. Most frequent causes: Flood (12), Severe Storm (8), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| August 2024 | Flood | Severe Storms, Straight-Line Winds, and Flooding |
| June 2022 | Severe Storm | Severe Storm, Straight-Line Winds, Tornadoes, and Flooding |
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| November 2019 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| September 2019 | Flood | Severe Storms and Flooding |
| June 2019 | Flood | Severe Winter Storm, Snowstorm, and Flooding |
| July 2014 | Flood | Severe Storms, Tornadoes, and Flooding |
| May 2011 | Flood | Flooding |
| May 2010 | Flood | Flooding |
Showing the 10 most recent of 25 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Hanson County?
Hanson County has a composite FEMA National Risk Index score of 14.8 out of 100, placing it in the Very Low category and the 15th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Hanson County?
The three highest-rated hazards are Drought (Medium, $692K EAL), Ice Storm (Medium, $142K EAL), Hail (Low, $322K EAL). These account for most of the county's expected annual losses.
How does Hanson County compare to other South Dakota counties?
Hanson County ranks #39 of 66 South Dakota counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Hanson County had?
FEMA records 25 federal disaster declarations for Hanson County since 1969, most often 12 for flood events and 8 for severe storm events. The most recent was Severe Storms, Straight-Line Winds, and Flooding, declared in August 2024.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Hanson County's $4M EAL is a statistical average, not a guarantee for any specific year or address.