Carroll County, Iowa Natural Disaster Risk
FEMA National Risk Index assessment · IA
LowComposite Risk Score
National percentile: 58th
Carroll County faces low composite natural disaster risk (NRI Risk Index score 57.6, 58th national percentile), driven primarily by hail and drought exposure. Expected annual loss across all 18 hazard types is $23M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Carroll County at low composite risk, with a National Risk Index score of 57.6 out of 100 — placing it in the 58th 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 hail (ice stones from severe thunderstorms that damage property and crops) at High risk — $5M in expected annual loss and about 5.81 events per year; drought (extended dry periods that stress water supplies and agriculture) at High risk — $3M in expected annual loss and about 12.31 events per year; and tornado (violently rotating columns of air capable of catastrophic local damage) at Medium risk — $6M in expected annual loss and about 0.51 events per year. Across all hazards, FEMA estimates $23M in expected annual loss for a population of 21K.
Beyond physical exposure, Carroll 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.
History supports the rating: Carroll County has received 16 federal disaster declarations since 1965, including 7 for flood events and 4 for severe storm events. The most recent was Covid-19 Pandemic (biological), declared in March 2020.
Among 99 Iowa counties, Carroll County ranks #21 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Hail | High | 5.81 / yr | $5M |
| Drought | High | 12.31 / yr | $3M |
| Tornado | Medium | 0.51 / yr | $6M |
| Strong Wind | Medium | 4.80 / yr | $2M |
| Ice Storm | Medium | 0.66 / yr | $189K |
| Cold Wave | Low | 7.47 / yr | $2M |
| Winter Weather | Low | 14.74 / yr | $83K |
| Landslide | Very Low | 0.10 / yr | $1K |
| Riverine Flood | Low | 1.82 / yr | $5M |
| Wildfire | Very Low | 0.00 / yr | $15K |
| Lightning | Very Low | 43.62 / yr | $87K |
| Heat Wave | Very Low | 5.74 / yr | $74K |
| Earthquake | Very Low | 0.00 / yr | $32K |
| Hurricane | Very Low | 0.01 / yr | $6K |
| 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
Carroll County has received 16 federal disaster declarations since 1965, most recently Covid-19 Pandemic in March 2020. Most frequent causes: Flood (7), Severe Storm (4), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| March 2019 | Flood | Severe Storms and Flooding |
| March 2010 | Severe Storm | Severe Winter Storm |
| February 2010 | Severe Storm | Severe Winter Storms and Snowstorm |
| May 2008 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| March 2007 | Snowstorm | Snow |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| May 2004 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| July 1998 | Flood | Severe Storms, Tornadoes 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 Carroll County?
Carroll County has a composite FEMA National Risk Index score of 57.6 out of 100, placing it in the Low category and the 58th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Carroll County?
The three highest-rated hazards are Hail (High, $5M EAL), Drought (High, $3M EAL), Tornado (Medium, $6M EAL). These account for most of the county's expected annual losses.
How does Carroll County compare to other Iowa counties?
Carroll County ranks #21 of 99 Iowa counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Carroll County had?
FEMA records 16 federal disaster declarations for Carroll County since 1965, most often 7 for flood events and 4 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. Carroll County's $23M EAL is a statistical average, not a guarantee for any specific year or address.