Sanborn County, South Dakota Natural Disaster Risk
FEMA National Risk Index assessment · SD
Very LowComposite Risk Score
National percentile: 4th
Sanborn County faces very low composite natural disaster risk (NRI Risk Index score 3.6, 4th national percentile), driven primarily by wildfire and drought exposure. Expected annual loss across all 18 hazard types is $4M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Sanborn County at very low composite risk, with a National Risk Index score of 3.6 out of 100 — placing it in the 4th 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 Sanborn County's expected losses come from wildfire (uncontrolled fires that spread across wildland and into communities) at Low risk — $204K in expected annual loss and about 0.00 events per year; drought (extended dry periods that stress water supplies and agriculture) at Low risk — $509K in expected annual loss and about 13.86 events per year; and ice storm (freezing rain that coats surfaces in heavy, damaging ice) at Low risk — $142K in expected annual loss and about 0.48 events per year. Across all hazards, FEMA estimates $4M in expected annual loss for a population of 2K.
Beyond physical exposure, Sanborn County has a very low social vulnerability rating (how susceptible the population is to harm) and a high community resilience rating (its capacity to prepare for and recover from disasters). A less vulnerable population paired with strong resilience helps the community absorb and recover from events.
The federal record bears this out: Sanborn County has received 22 federal disaster declarations since 1969, including 10 for flood events and 7 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, Sanborn County ranks #62 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Wildfire | Low | 0.00 / yr | $204K |
| Drought | Low | 13.86 / yr | $509K |
| Ice Storm | Low | 0.48 / yr | $142K |
| Hail | Low | 4.82 / yr | $267K |
| Winter Weather | Low | 16.58 / yr | $61K |
| Cold Wave | Low | 8.89 / yr | $529K |
| Tornado | Low | 0.32 / yr | $598K |
| Landslide | Very Low | 0.06 / yr | $129 |
| Heat Wave | Very Low | 5.89 / yr | $42K |
| Strong Wind | Very Low | 3.16 / yr | $147K |
| Earthquake | Very Low | 0.00 / yr | $18K |
| Riverine Flood | Very Low | 2.43 / yr | $1M |
| Lightning | Very Low | 35.83 / yr | $7K |
| 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
Sanborn County has received 22 federal disaster declarations since 1969, most recently Severe Storms, Straight-Line Winds, and Flooding in August 2024. Most frequent causes: Flood (10), Severe Storm (7), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| August 2024 | Flood | Severe Storms, Straight-Line Winds, 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 |
| May 2011 | Flood | Flooding |
| September 2010 | Severe Storm | Severe Storms and Flooding |
| May 2010 | Flood | Flooding |
| May 2007 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
Showing the 10 most recent of 22 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Sanborn County?
Sanborn County has a composite FEMA National Risk Index score of 3.6 out of 100, placing it in the Very Low category and the 4th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Sanborn County?
The three highest-rated hazards are Wildfire (Low, $204K EAL), Drought (Low, $509K EAL), Ice Storm (Low, $142K EAL). These account for most of the county's expected annual losses.
How does Sanborn County compare to other South Dakota counties?
Sanborn County ranks #62 of 66 South Dakota counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Sanborn County had?
FEMA records 22 federal disaster declarations for Sanborn County since 1969, most often 10 for flood events and 7 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. Sanborn County's $4M EAL is a statistical average, not a guarantee for any specific year or address.