Sac County, Iowa Natural Disaster Risk
FEMA National Risk Index assessment · IA
Very LowComposite Risk Score
National percentile: 27th
Sac County faces very low composite natural disaster risk (NRI Risk Index score 27.3, 27th national percentile), driven primarily by drought and hail exposure. Expected annual loss across all 18 hazard types is $15M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Sac County carries a very low composite natural disaster risk, with a National Risk Index score of 27.3 out of 100 — placing it in the 27th 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 drought (extended dry periods that stress water supplies and agriculture) at High risk — $3M in expected annual loss and about 15.19 events per year; hail (ice stones from severe thunderstorms that damage property and crops) at Medium risk — $3M in expected annual loss and about 5.37 events per year; and tornado (violently rotating columns of air capable of catastrophic local damage) at Low risk — $3M in expected annual loss and about 0.48 events per year. Across all hazards, FEMA estimates $15M in expected annual loss for a population of 10K.
Beyond physical exposure, Sac 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.
History supports the rating: Sac County has received 19 federal disaster declarations since 1965, including 9 for severe storm events and 5 for flood events. The most recent was Severe Storms, Straight-Line Winds, and Tornadoes (severe storm), declared in February 2022.
Among 99 Iowa counties, Sac County ranks #71 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Drought | High | 15.19 / yr | $3M |
| Hail | Medium | 5.37 / yr | $3M |
| Tornado | Low | 0.48 / yr | $3M |
| Ice Storm | Low | 0.63 / yr | $186K |
| Cold Wave | Low | 8.58 / yr | $1M |
| Winter Weather | Low | 15.63 / yr | $67K |
| Strong Wind | Low | 4.10 / yr | $463K |
| Landslide | Very Low | 0.07 / yr | $310 |
| Riverine Flood | Very Low | 1.61 / yr | $3M |
| Heat Wave | Very Low | 5.11 / yr | $69K |
| Lightning | Very Low | 42.78 / yr | $77K |
| Earthquake | Very Low | 0.00 / yr | $16K |
| Wildfire | Very Low | 0.00 / yr | $5K |
| 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
Sac County has received 19 federal disaster declarations since 1965, most recently Severe Storms, Straight-Line Winds, and Tornadoes in February 2022. Most frequent causes: Severe Storm (9), Flood (5), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| February 2022 | Severe Storm | Severe Storms, Straight-Line Winds, and Tornadoes |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| March 2019 | Flood | Severe Storms and Flooding |
| July 2014 | Flood | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| July 2013 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| May 2011 | Severe Storm | Severe Storms, Tornadoes, and Straight-Line Winds |
| March 2010 | Severe Storm | Severe Winter Storm |
| February 2010 | Severe Storm | Severe Winter Storms and Snowstorm |
| May 2007 | Severe Storm | Severe Storms, Flooding, and Tornadoes |
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 Sac County?
Sac County has a composite FEMA National Risk Index score of 27.3 out of 100, placing it in the Very Low category and the 27th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Sac County?
The three highest-rated hazards are Drought (High, $3M EAL), Hail (Medium, $3M EAL), Tornado (Low, $3M EAL). These account for most of the county's expected annual losses.
How does Sac County compare to other Iowa counties?
Sac County ranks #71 of 99 Iowa counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Sac County had?
FEMA records 19 federal disaster declarations for Sac County since 1965, most often 9 for severe storm events and 5 for flood events. The most recent was Severe Storms, Straight-Line Winds, and Tornadoes, declared in February 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. Sac County's $15M EAL is a statistical average, not a guarantee for any specific year or address.