Ziebach County, South Dakota Natural Disaster Risk
FEMA National Risk Index assessment · SD
Very LowComposite Risk Score
National percentile: 25th
Ziebach County faces very low composite natural disaster risk (NRI Risk Index score 25.2, 25th national percentile), driven primarily by cold wave and wildfire exposure. Expected annual loss across all 18 hazard types is $5M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Ziebach County carries a very low composite natural disaster risk, with a National Risk Index score of 25.2 out of 100 — placing it in the 25th 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 cold wave (prolonged spells of dangerously low temperatures) at Medium risk — $3M in expected annual loss and about 7.79 events per year; wildfire (uncontrolled fires that spread across wildland and into communities) at Low risk — $160K in expected annual loss and about 0.00 events per year; and winter weather (heavy snow, blizzards, and hazardous winter conditions) at Medium risk — $54K in expected annual loss and about 14.63 events per year. Across all hazards, FEMA estimates $5M in expected annual loss for a population of 2K.
Beyond physical exposure, Ziebach County has a very high social vulnerability rating (how susceptible the population is to harm) and a very low 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.
The federal record bears this out: Ziebach County has received 21 federal disaster declarations since 1976, including 10 for severe storm events and 4 for flood events. The most recent was Severe Winter Storms and Snowstorm (winter storm), declared in February 2023.
Among 66 South Dakota counties, Ziebach County ranks #29 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Cold Wave | Medium | 7.79 / yr | $3M |
| Wildfire | Low | 0.00 / yr | $160K |
| Winter Weather | Medium | 14.63 / yr | $54K |
| Strong Wind | Medium | 2.47 / yr | $312K |
| Ice Storm | Low | 0.48 / yr | $34K |
| Hail | Very Low | 2.64 / yr | $68K |
| Drought | Very Low | 55.15 / yr | $14K |
| Landslide | Very Low | 0.74 / yr | $87 |
| Heat Wave | Very Low | 2.26 / yr | $20K |
| Tornado | Very Low | 0.34 / yr | $42K |
| Earthquake | Very Low | 0.00 / yr | $5K |
| Riverine Flood | Very Low | 1.18 / yr | $640K |
| Lightning | Very Low | 33.24 / yr | $15K |
| 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
Ziebach County has received 21 federal disaster declarations since 1976, most recently Severe Winter Storms and Snowstorm in February 2023. Most frequent causes: Severe Storm (10), Flood (4), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| February 2023 | Winter Storm | Severe Winter Storms and Snowstorm |
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| September 2019 | Flood | Severe Storms and Flooding |
| June 2019 | Flood | Severe Winter Storm, Snowstorm, and Flooding |
| February 2017 | Severe Storm | Severe Winter Storm |
| July 2014 | Flood | Severe Storms, Tornadoes, and Flooding |
| November 2013 | Severe Storm | Severe Winter Storm, Snowstorm, and Flooding |
| July 2010 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| May 2010 | Severe Storm | Severe Winter Storm |
Showing the 10 most recent of 21 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Ziebach County?
Ziebach County has a composite FEMA National Risk Index score of 25.2 out of 100, placing it in the Very Low category and the 25th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Ziebach County?
The three highest-rated hazards are Cold Wave (Medium, $3M EAL), Wildfire (Low, $160K EAL), Winter Weather (Medium, $54K EAL). These account for most of the county's expected annual losses.
How does Ziebach County compare to other South Dakota counties?
Ziebach County ranks #29 of 66 South Dakota counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Ziebach County had?
FEMA records 21 federal disaster declarations for Ziebach County since 1976, most often 10 for severe storm events and 4 for flood events. The most recent was Severe Winter Storms and Snowstorm, declared in February 2023.
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. Ziebach County's $5M EAL is a statistical average, not a guarantee for any specific year or address.