Yankton County, South Dakota Natural Disaster Risk
FEMA National Risk Index assessment · SD
LowComposite Risk Score
National percentile: 63th
Yankton County faces low composite natural disaster risk (NRI Risk Index score 63.4, 63th national percentile), driven primarily by drought and winter weather exposure. Expected annual loss across all 18 hazard types is $19M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Yankton County at low composite risk, with a National Risk Index score of 63.4 out of 100 — placing it in the 63rd 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 drought (extended dry periods that stress water supplies and agriculture) at High risk — $2M in expected annual loss and about 25.11 events per year; winter weather (heavy snow, blizzards, and hazardous winter conditions) at High risk — $414K in expected annual loss and about 15.84 events per year; and tornado (violently rotating columns of air capable of catastrophic local damage) at Medium risk — $5M in expected annual loss and about 0.40 events per year. Across all hazards, FEMA estimates $19M in expected annual loss for a population of 23K.
Beyond physical exposure, Yankton County has a high 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). Higher vulnerability is partly offset by strong community resilience and recovery capacity.
The federal record bears this out: Yankton County has received 16 federal disaster declarations since 1976, including 6 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, Yankton County ranks #5 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Drought | High | 25.11 / yr | $2M |
| Winter Weather | High | 15.84 / yr | $414K |
| Tornado | Medium | 0.40 / yr | $5M |
| Hail | Medium | 6.28 / yr | $1M |
| Ice Storm | High | 0.87 / yr | $409K |
| Lightning | Medium | 38.61 / yr | $564K |
| Wildfire | Low | 0.00 / yr | $230K |
| Cold Wave | Medium | 6.42 / yr | $2M |
| Landslide | Low | 0.09 / yr | $4K |
| Heat Wave | Low | 6.74 / yr | $563K |
| Strong Wind | Medium | 3.68 / yr | $567K |
| Riverine Flood | Low | 2.32 / yr | $7M |
| Earthquake | Very Low | 0.00 / yr | $57K |
| 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
Yankton County has received 16 federal disaster declarations since 1976, most recently Severe Storms, Straight-Line Winds, and Flooding in August 2024. Most frequent causes: Flood (6), Severe Storm (6), 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 |
| March 2010 | Severe Storm | Severe Winter Storm and Snowstorm |
| May 2007 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| September 2005 | Coastal Storm | Hurricane Katrina Evacuation |
| July 2004 | Severe Storm | Severe Storms and Flooding |
Showing the 10 most recent of 16 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Yankton County?
Yankton County has a composite FEMA National Risk Index score of 63.4 out of 100, placing it in the Low category and the 63th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Yankton County?
The three highest-rated hazards are Drought (High, $2M EAL), Winter Weather (High, $414K EAL), Tornado (Medium, $5M EAL). These account for most of the county's expected annual losses.
How does Yankton County compare to other South Dakota counties?
Yankton County ranks #5 of 66 South Dakota counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Yankton County had?
FEMA records 16 federal disaster declarations for Yankton County since 1976, most often 6 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. Yankton County's $19M EAL is a statistical average, not a guarantee for any specific year or address.