McPherson County, South Dakota Natural Disaster Risk
FEMA National Risk Index assessment · SD
Very LowComposite Risk Score
National percentile: 11th
McPherson County faces very low composite natural disaster risk (NRI Risk Index score 11.1, 11th national percentile), driven primarily by winter weather and cold wave exposure. Expected annual loss across all 18 hazard types is $4M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
McPherson County carries a very low composite natural disaster risk, with a National Risk Index score of 11.1 out of 100 — placing it in the 11th 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.
The county's risk is driven primarily by winter weather (heavy snow, blizzards, and hazardous winter conditions) at Medium risk — $128K in expected annual loss and about 18.63 events per year; cold wave (prolonged spells of dangerously low temperatures) at Medium risk — $2M in expected annual loss and about 12.47 events per year; and hail (ice stones from severe thunderstorms that damage property and crops) at Low risk — $409K in expected annual loss and about 3.45 events per year. Across all hazards, FEMA estimates $4M in expected annual loss for a population of 2K.
Beyond physical exposure, McPherson County has a very 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: McPherson County has received 17 federal disaster declarations since 1969, including 7 for severe storm events and 5 for flood events. The most recent was Severe Storm, Straight-Line Winds, Tornadoes, and Flooding (severe storm), declared in August 2022.
Among 66 South Dakota counties, McPherson County ranks #42 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Winter Weather | Medium | 18.63 / yr | $128K |
| Cold Wave | Medium | 12.47 / yr | $2M |
| Hail | Low | 3.45 / yr | $409K |
| Wildfire | Low | 0.00 / yr | $127K |
| Ice Storm | Low | 0.51 / yr | $49K |
| Drought | Low | 11.64 / yr | $42K |
| Strong Wind | Low | 2.30 / yr | $221K |
| Tornado | Very Low | 0.46 / yr | $242K |
| Heat Wave | Very Low | 2.63 / yr | $19K |
| Earthquake | Very Low | 0.00 / yr | $6K |
| Riverine Flood | Very Low | 0.64 / yr | $788K |
| Landslide | Very Low | 0.13 / yr | $2 |
| Lightning | Very Low | 31.27 / yr | $3K |
| 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
McPherson County has received 17 federal disaster declarations since 1969, most recently Severe Storm, Straight-Line Winds, Tornadoes, and Flooding in August 2022. Most frequent causes: Severe Storm (7), Flood (5), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| August 2022 | Severe Storm | Severe Storm, Straight-Line Winds, Tornadoes, and Flooding |
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| June 2019 | Flood | Severe Winter Storm, Snowstorm, and Flooding |
| February 2017 | Severe Storm | Severe Winter Storm |
| May 2010 | Flood | Flooding |
| March 2010 | Severe Storm | Severe Winter Storm |
| June 2009 | Severe Storm | Severe Storms and Flooding |
| September 2005 | Coastal Storm | Hurricane Katrina Evacuation |
| April 1997 | Flood | Severe Flooding, Sever Winter Storms,Heavy Rains High Winds |
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 McPherson County?
McPherson County has a composite FEMA National Risk Index score of 11.1 out of 100, placing it in the Very Low category and the 11th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in McPherson County?
The three highest-rated hazards are Winter Weather (Medium, $128K EAL), Cold Wave (Medium, $2M EAL), Hail (Low, $409K EAL). These account for most of the county's expected annual losses.
How does McPherson County compare to other South Dakota counties?
McPherson County ranks #42 of 66 South Dakota counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has McPherson County had?
FEMA records 17 federal disaster declarations for McPherson County since 1969, most often 7 for severe storm events and 5 for flood events. The most recent was Severe Storm, Straight-Line Winds, Tornadoes, and Flooding, declared in August 2022.
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. McPherson County's $4M EAL is a statistical average, not a guarantee for any specific year or address.