Charles Mix County, South Dakota Natural Disaster Risk
FEMA National Risk Index assessment · SD
LowComposite Risk Score
National percentile: 49th
Charles Mix County faces low composite natural disaster risk (NRI Risk Index score 48.5, 49th national percentile), driven primarily by cold wave and drought exposure. Expected annual loss across all 18 hazard types is $13M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Charles Mix County carries a low composite natural disaster risk, with a National Risk Index score of 48.5 out of 100 — placing it in the 49th national percentile and below the national average for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
The county's risk is driven primarily by cold wave (prolonged spells of dangerously low temperatures) at Medium risk — $5M in expected annual loss and about 5.84 events per year; drought (extended dry periods that stress water supplies and agriculture) at Medium risk — $1M in expected annual loss and about 26.23 events per year; and winter weather (heavy snow, blizzards, and hazardous winter conditions) at Medium risk — $225K in expected annual loss and about 15.47 events per year. Across all hazards, FEMA estimates $13M in expected annual loss for a population of 9K.
Beyond physical exposure, Charles Mix County has a high social vulnerability rating (how susceptible the population is to harm) and a medium community resilience rating (its capacity to prepare for and recover from disasters). That combination — a more vulnerable population with limited resilience — can amplify the human cost of any given event.
History supports the rating: Charles Mix County has received 17 federal disaster declarations since 1976, including 7 for flood events and 5 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, Charles Mix County ranks #13 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Cold Wave | Medium | 5.84 / yr | $5M |
| Drought | Medium | 26.23 / yr | $1M |
| Winter Weather | Medium | 15.47 / yr | $225K |
| Wildfire | Low | 0.00 / yr | $262K |
| Hail | Medium | 5.02 / yr | $627K |
| Ice Storm | Medium | 0.60 / yr | $261K |
| Tornado | Low | 0.60 / yr | $1M |
| Riverine Flood | Low | 1.71 / yr | $4M |
| Strong Wind | Low | 2.63 / yr | $252K |
| Lightning | Low | 37.29 / yr | $88K |
| Earthquake | Very Low | 0.00 / yr | $50K |
| Heat Wave | Very Low | 6.32 / yr | $94K |
| Landslide | Very Low | 0.19 / yr | $70 |
| 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
Charles Mix County has received 17 federal disaster declarations since 1976, most recently Severe Storms, Straight-Line Winds, and Flooding in August 2024. Most frequent causes: Flood (7), Severe Storm (5), 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 |
| June 2019 | Flood | Severe Winter Storm, Snowstorm, and Flooding |
| May 2011 | Flood | Flooding |
| May 2010 | Flood | Flooding |
| July 2008 | Severe Storm | Severe Storms and Flooding |
| December 2005 | Severe Storm | Severe Winter Storm |
| 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 Charles Mix County?
Charles Mix County has a composite FEMA National Risk Index score of 48.5 out of 100, placing it in the Low category and the 49th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Charles Mix County?
The three highest-rated hazards are Cold Wave (Medium, $5M EAL), Drought (Medium, $1M EAL), Winter Weather (Medium, $225K EAL). These account for most of the county's expected annual losses.
How does Charles Mix County compare to other South Dakota counties?
Charles Mix County ranks #13 of 66 South Dakota counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Charles Mix County had?
FEMA records 17 federal disaster declarations for Charles Mix County since 1976, most often 7 for flood events and 5 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. Charles Mix County's $13M EAL is a statistical average, not a guarantee for any specific year or address.