Marshall County, Iowa Natural Disaster Risk
FEMA National Risk Index assessment · IA
LowComposite Risk Score
National percentile: 62th
Marshall County faces low composite natural disaster risk (NRI Risk Index score 62.5, 62th national percentile), driven primarily by drought and strong wind exposure. Expected annual loss across all 18 hazard types is $23M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Marshall County is low, with a National Risk Index score of 62.5 out of 100 — placing it in the 62nd 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 drought (extended dry periods that stress water supplies and agriculture) at High risk — $4M in expected annual loss and about 7.08 events per year; strong wind (damaging straight-line winds outside of tornadoes and hurricanes) at High risk — $2M in expected annual loss and about 6.43 events per year; and winter weather (heavy snow, blizzards, and hazardous winter conditions) at Medium risk — $268K in expected annual loss and about 15.63 events per year. Across all hazards, FEMA estimates $23M in expected annual loss for a population of 40K.
Beyond physical exposure, Marshall County has a low social vulnerability rating (how susceptible the population is to harm) and a 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: Marshall County has received 20 federal disaster declarations since 1965, including 9 for flood events and 8 for severe storm events. The most recent was Severe Storms, Tornadoes, and Flooding (severe storm), declared in May 2024.
Among 99 Iowa counties, Marshall County ranks #14 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Drought | High | 7.08 / yr | $4M |
| Strong Wind | High | 6.43 / yr | $2M |
| Winter Weather | Medium | 15.63 / yr | $268K |
| Tornado | Medium | 0.60 / yr | $4M |
| Hail | Medium | 6.16 / yr | $926K |
| Riverine Flood | Low | 2.43 / yr | $10M |
| Wildfire | Very Low | 0.00 / yr | $97K |
| Landslide | Very Low | 0.11 / yr | $1K |
| Ice Storm | Low | 0.56 / yr | $84K |
| Cold Wave | Low | 7.89 / yr | $685K |
| Earthquake | Very Low | 0.00 / yr | $57K |
| Lightning | Low | 43.05 / yr | $93K |
| Hurricane | Very Low | 0.01 / yr | $4K |
| Heat Wave | Very Low | 4.89 / yr | $18K |
| 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
Marshall County has received 20 federal disaster declarations since 1965, most recently Severe Storms, Tornadoes, and Flooding in May 2024. Most frequent causes: Flood (9), Severe Storm (8), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| May 2024 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| August 2020 | Severe Storm | Severe Storms |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| March 2019 | Flood | Severe Storms and Flooding |
| September 2018 | Severe Storm | Severe Storm and Tornadoes |
| July 2013 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| August 2011 | Severe Storm | Severe Storms, Straight-Line Winds, and Flooding |
| May 2008 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| March 2007 | Severe Storm | Severe Winter Storms |
Showing the 10 most recent of 20 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Marshall County?
Marshall County has a composite FEMA National Risk Index score of 62.5 out of 100, placing it in the Low category and the 62th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Marshall County?
The three highest-rated hazards are Drought (High, $4M EAL), Strong Wind (High, $2M EAL), Winter Weather (Medium, $268K EAL). These account for most of the county's expected annual losses.
How does Marshall County compare to other Iowa counties?
Marshall County ranks #14 of 99 Iowa counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Marshall County had?
FEMA records 20 federal disaster declarations for Marshall County since 1965, most often 9 for flood events and 8 for severe storm events. The most recent was Severe Storms, Tornadoes, and Flooding, declared in May 2024.
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. Marshall County's $23M EAL is a statistical average, not a guarantee for any specific year or address.