Clay County, South Dakota Natural Disaster Risk
FEMA National Risk Index assessment · SD
Very LowComposite Risk Score
National percentile: 20th
Clay County faces very low composite natural disaster risk (NRI Risk Index score 20.5, 20th national percentile), driven primarily by drought and winter weather exposure. Expected annual loss across all 18 hazard types is $12M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Clay County at very low composite risk, with a National Risk Index score of 20.5 out of 100 — placing it in the 20th 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 Clay County's expected losses come from drought (extended dry periods that stress water supplies and agriculture) at Medium risk — $955K in expected annual loss and about 30.72 events per year; winter weather (heavy snow, blizzards, and hazardous winter conditions) at Medium risk — $224K in expected annual loss and about 15.42 events per year; and hail (ice stones from severe thunderstorms that damage property and crops) at Low risk — $715K in expected annual loss and about 6.50 events per year. Across all hazards, FEMA estimates $12M in expected annual loss for a population of 15K.
Beyond physical exposure, Clay 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: Clay County has received 19 federal disaster declarations since 1969, including 9 for flood events and 6 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, Clay County ranks #32 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Drought | Medium | 30.72 / yr | $955K |
| Winter Weather | Medium | 15.42 / yr | $224K |
| Hail | Low | 6.50 / yr | $715K |
| Ice Storm | Medium | 0.95 / yr | $231K |
| Tornado | Low | 0.35 / yr | $3M |
| Wildfire | Very Low | 0.00 / yr | $46K |
| Lightning | Low | 39.35 / yr | $218K |
| Landslide | Very Low | 0.05 / yr | $570 |
| Strong Wind | Low | 4.04 / yr | $488K |
| Heat Wave | Very Low | 6.58 / yr | $215K |
| Riverine Flood | Very Low | 2.11 / yr | $5M |
| Cold Wave | Very Low | 6.32 / yr | $434K |
| Earthquake | Very Low | 0.00 / yr | $21K |
| 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
Clay County has received 19 federal disaster declarations since 1969, most recently Severe Storms, Straight-Line Winds, and Flooding in August 2024. Most frequent causes: Flood (9), Severe Storm (6), 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 |
| June 2019 | Flood | Severe Winter Storm, Snowstorm, and Flooding |
| July 2014 | Flood | Severe Storms, Tornadoes, and Flooding |
| May 2011 | Flood | Flooding |
| September 2010 | Severe Storm | Severe Storms and Flooding |
| May 2010 | Flood | Flooding |
| March 2010 | Severe Storm | Severe Winter Storm and Snowstorm |
Showing the 10 most recent of 19 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Clay County?
Clay County has a composite FEMA National Risk Index score of 20.5 out of 100, placing it in the Very Low category and the 20th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Clay County?
The three highest-rated hazards are Drought (Medium, $955K EAL), Winter Weather (Medium, $224K EAL), Hail (Low, $715K EAL). These account for most of the county's expected annual losses.
How does Clay County compare to other South Dakota counties?
Clay County ranks #32 of 66 South Dakota counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Clay County had?
FEMA records 19 federal disaster declarations for Clay County since 1969, most often 9 for flood events and 6 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. Clay County's $12M EAL is a statistical average, not a guarantee for any specific year or address.