Minnehaha County, South Dakota Natural Disaster Risk
FEMA National Risk Index assessment · SD
MediumComposite Risk Score
National percentile: 90th
Minnehaha County faces medium composite natural disaster risk (NRI Risk Index score 89.5, 90th national percentile), driven primarily by ice storm and tornado exposure. Expected annual loss across all 18 hazard types is $104M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Minnehaha County at medium composite risk, with a National Risk Index score of 89.5 out of 100 — placing it in the 90th national percentile and near the national midpoint for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Risk here concentrates in ice storm (freezing rain that coats surfaces in heavy, damaging ice) at Very High risk — $5M in expected annual loss and about 1.11 events per year; tornado (violently rotating columns of air capable of catastrophic local damage) at High risk — $36M in expected annual loss and about 0.67 events per year; and winter weather (heavy snow, blizzards, and hazardous winter conditions) at High risk — $1M in expected annual loss and about 17.63 events per year. Across all hazards, FEMA estimates $104M in expected annual loss for a population of 197K.
Beyond physical exposure, Minnehaha County has a very low 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). A less vulnerable population paired with strong resilience helps the community absorb and recover from events.
The county's disaster history tells the same story: Minnehaha County has received 17 federal disaster declarations since 1969, including 8 for severe storm events and 5 for flood events. The most recent was Severe Storms, Straight-Line Winds, and Flooding (flood), declared in August 2024.
Among 66 South Dakota counties, Minnehaha County ranks #1 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Ice Storm | Very High | 1.11 / yr | $5M |
| Tornado | High | 0.67 / yr | $36M |
| Winter Weather | High | 17.63 / yr | $1M |
| Cold Wave | High | 8.53 / yr | $17M |
| Hail | Medium | 5.93 / yr | $3M |
| Strong Wind | High | 3.96 / yr | $3M |
| Heat Wave | Medium | 5.58 / yr | $3M |
| Riverine Flood | Medium | 4.50 / yr | $34M |
| Drought | Medium | 15.19 / yr | $807K |
| Wildfire | Low | 0.00 / yr | $243K |
| Lightning | Low | 37.73 / yr | $359K |
| Landslide | Very Low | 0.11 / yr | $2K |
| Earthquake | Very Low | 0.00 / yr | $162K |
| 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
Minnehaha County has received 17 federal disaster declarations since 1969, most recently Severe Storms, Straight-Line Winds, and Flooding in August 2024. Most frequent causes: Severe Storm (8), Flood (5), 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 |
| June 2019 | Flood | Severe Winter Storm, Snowstorm, and Flooding |
| July 2014 | Flood | Severe Storms, Tornadoes, and Flooding |
| May 2013 | Severe Storm | Severe Winter Storm and Snowstorm |
| September 2010 | Severe Storm | Severe Storms and Flooding |
| September 2005 | Coastal Storm | Hurricane Katrina Evacuation |
Showing the 10 most recent of 17 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Minnehaha County?
Minnehaha County has a composite FEMA National Risk Index score of 89.5 out of 100, placing it in the Medium category and the 90th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Minnehaha County?
The three highest-rated hazards are Ice Storm (Very High, $5M EAL), Tornado (High, $36M EAL), Winter Weather (High, $1M EAL). These account for most of the county's expected annual losses.
How does Minnehaha County compare to other South Dakota counties?
Minnehaha County ranks #1 of 66 South Dakota counties for overall natural disaster risk, with a medium rating.
How many federally declared disasters has Minnehaha County had?
FEMA records 17 federal disaster declarations for Minnehaha County since 1969, most often 8 for severe storm events and 5 for flood 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. Minnehaha County's $104M EAL is a statistical average, not a guarantee for any specific year or address.