Warren County, Iowa Natural Disaster Risk
FEMA National Risk Index assessment · IA
Very LowComposite Risk Score
National percentile: 36th
Warren County faces very low composite natural disaster risk (NRI Risk Index score 36.1, 36th national percentile), driven primarily by drought and landslide exposure. Expected annual loss across all 18 hazard types is $19M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Warren County is very low, with a National Risk Index score of 36.1 out of 100 — placing it in the 36th 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 6.15 events per year; landslide (downhill movement of rock, soil, and debris on unstable slopes) at Low risk — $12K in expected annual loss and about 0.27 events per year; and tornado (violently rotating columns of air capable of catastrophic local damage) at Medium risk — $4M in expected annual loss and about 0.50 events per year. Across all hazards, FEMA estimates $19M in expected annual loss for a population of 52K.
Beyond physical exposure, Warren 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 federal record bears this out: Warren County has received 17 federal disaster declarations since 1973, including 6 for flood events and 5 for severe storm events. The most recent was Covid-19 Pandemic (biological), declared in March 2020.
Among 99 Iowa counties, Warren County ranks #50 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Drought | High | 6.15 / yr | $3M |
| Landslide | Low | 0.27 / yr | $12K |
| Tornado | Medium | 0.50 / yr | $4M |
| Heat Wave | Low | 7.53 / yr | $1M |
| Lightning | Medium | 45.36 / yr | $560K |
| Wildfire | Very Low | 0.00 / yr | $132K |
| Strong Wind | Medium | 5.70 / yr | $1M |
| Ice Storm | Low | 0.84 / yr | $148K |
| Hail | Low | 5.88 / yr | $416K |
| Cold Wave | Low | 5.16 / yr | $1M |
| Riverine Flood | Low | 2.86 / yr | $7M |
| Winter Weather | Low | 12.95 / yr | $39K |
| Earthquake | Very Low | 0.00 / yr | $49K |
| Hurricane | Very Low | 0.01 / yr | $1K |
| 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
Warren County has received 17 federal disaster declarations since 1973, most recently Covid-19 Pandemic in March 2020. Most frequent causes: Flood (6), Severe Storm (5), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| August 2018 | Severe Storm | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| July 2015 | Severe Storm | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| May 2013 | Flood | Severe Storms, Straight-Line Winds, and Flooding |
| July 2010 | Severe Storm | Severe Storms, Flooding, and Tornadoes |
| May 2008 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| January 2008 | Severe Ice Storm | Severe Winter Storm |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| May 2004 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
Showing the 10 most recent of 17 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Warren County?
Warren County has a composite FEMA National Risk Index score of 36.1 out of 100, placing it in the Very Low category and the 36th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Warren County?
The three highest-rated hazards are Drought (High, $3M EAL), Landslide (Low, $12K EAL), Tornado (Medium, $4M EAL). These account for most of the county's expected annual losses.
How does Warren County compare to other Iowa counties?
Warren County ranks #50 of 99 Iowa counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Warren County had?
FEMA records 17 federal disaster declarations for Warren County since 1973, most often 6 for flood events and 5 for severe storm events. The most recent was Covid-19 Pandemic, declared in March 2020.
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. Warren County's $19M EAL is a statistical average, not a guarantee for any specific year or address.