Greene County, Iowa Natural Disaster Risk
FEMA National Risk Index assessment · IA
Very LowComposite Risk Score
National percentile: 32th
Greene County faces very low composite natural disaster risk (NRI Risk Index score 31.8, 32th national percentile), driven primarily by drought and cold wave exposure. Expected annual loss across all 18 hazard types is $12M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Greene County is very low, with a National Risk Index score of 31.8 out of 100 — placing it in the 32nd 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.
Risk here concentrates in drought (extended dry periods that stress water supplies and agriculture) at High risk — $4M in expected annual loss and about 15.39 events per year; cold wave (prolonged spells of dangerously low temperatures) at Medium risk — $2M in expected annual loss and about 7.95 events per year; and tornado (violently rotating columns of air capable of catastrophic local damage) at Medium risk — $3M in expected annual loss and about 0.55 events per year. Across all hazards, FEMA estimates $12M in expected annual loss for a population of 9K.
Beyond physical exposure, Greene County has a 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: Greene County has received 19 federal disaster declarations since 1969, including 7 for severe storm events and 7 for flood events. The most recent was Severe Storms, Straight-Line Winds, and Tornadoes (severe storm), declared in February 2022.
Among 99 Iowa counties, Greene County ranks #59 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Drought | High | 15.39 / yr | $4M |
| Cold Wave | Medium | 7.95 / yr | $2M |
| Tornado | Medium | 0.55 / yr | $3M |
| Hail | Low | 6.13 / yr | $502K |
| Winter Weather | Low | 15.21 / yr | $65K |
| Ice Storm | Low | 0.62 / yr | $61K |
| Strong Wind | Low | 5.56 / yr | $481K |
| Landslide | Very Low | 0.07 / yr | $481 |
| Heat Wave | Very Low | 5.47 / yr | $46K |
| Hurricane | Very Low | 0.01 / yr | $4K |
| Riverine Flood | Very Low | 1.93 / yr | $2M |
| Earthquake | Very Low | 0.00 / yr | $13K |
| Wildfire | Very Low | 0.00 / yr | $4K |
| Lightning | Very Low | 44.06 / yr | $35K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Greene County has received 19 federal disaster declarations since 1969, most recently Severe Storms, Straight-Line Winds, and Tornadoes in February 2022. Most frequent causes: Severe Storm (7), Flood (7), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| February 2022 | Severe Storm | Severe Storms, Straight-Line Winds, and Tornadoes |
| August 2020 | Severe Storm | Severe Storms |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| March 2019 | Flood | Severe Storms and Flooding |
| July 2013 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| March 2010 | Severe Storm | Severe Winter Storm |
| May 2008 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| March 2007 | Snowstorm | Snow |
| March 2007 | Severe Storm | Severe Winter Storms |
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 Greene County?
Greene County has a composite FEMA National Risk Index score of 31.8 out of 100, placing it in the Very Low category and the 32th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Greene County?
The three highest-rated hazards are Drought (High, $4M EAL), Cold Wave (Medium, $2M EAL), Tornado (Medium, $3M EAL). These account for most of the county's expected annual losses.
How does Greene County compare to other Iowa counties?
Greene County ranks #59 of 99 Iowa counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Greene County had?
FEMA records 19 federal disaster declarations for Greene County since 1969, most often 7 for severe storm events and 7 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. Greene County's $12M EAL is a statistical average, not a guarantee for any specific year or address.