Grundy County, Iowa Natural Disaster Risk
FEMA National Risk Index assessment · IA
Very LowComposite Risk Score
National percentile: 13th
Grundy County faces very low composite natural disaster risk (NRI Risk Index score 13.1, 13th national percentile), driven primarily by drought and hail exposure. Expected annual loss across all 18 hazard types is $10M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Grundy County at very low composite risk, with a National Risk Index score of 13.1 out of 100 — placing it in the 13th 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 Medium risk — $3M in expected annual loss and about 13.39 events per year; hail (ice stones from severe thunderstorms that damage property and crops) at Low risk — $956K in expected annual loss and about 5.62 events per year; and winter weather (heavy snow, blizzards, and hazardous winter conditions) at Low risk — $144K in expected annual loss and about 17.53 events per year. Across all hazards, FEMA estimates $10M in expected annual loss for a population of 12K.
Beyond physical exposure, Grundy 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 county's disaster history tells the same story: Grundy County has received 15 federal disaster declarations since 1969, including 8 for severe storm events and 4 for flood events. The most recent was Severe Storms (severe storm), declared in August 2020.
Among 99 Iowa counties, Grundy County ranks #97 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Drought | Medium | 13.39 / yr | $3M |
| Hail | Low | 5.62 / yr | $956K |
| Winter Weather | Low | 17.53 / yr | $144K |
| Strong Wind | Low | 5.85 / yr | $739K |
| Tornado | Low | 0.52 / yr | $1M |
| Cold Wave | Low | 8.95 / yr | $736K |
| Ice Storm | Very Low | 0.46 / yr | $31K |
| Riverine Flood | Very Low | 1.61 / yr | $3M |
| Landslide | Very Low | 0.05 / yr | $64 |
| Earthquake | Very Low | 0.00 / yr | $17K |
| Heat Wave | Very Low | 4.00 / yr | $27K |
| Hurricane | Very Low | 0.01 / yr | $3K |
| Wildfire | Very Low | 0.00 / yr | $4K |
| Lightning | Very Low | 42.51 / yr | $20K |
| 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
Grundy County has received 15 federal disaster declarations since 1969, most recently Severe Storms in August 2020. Most frequent causes: Severe Storm (8), Flood (4), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| August 2020 | Severe Storm | Severe Storms |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| August 2014 | Severe Storm | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| July 2013 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| July 2013 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| May 2008 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| March 2007 | Severe Storm | Severe Winter Storms |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| May 2004 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
Showing the 10 most recent of 15 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Grundy County?
Grundy County has a composite FEMA National Risk Index score of 13.1 out of 100, placing it in the Very Low category and the 13th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Grundy County?
The three highest-rated hazards are Drought (Medium, $3M EAL), Hail (Low, $956K EAL), Winter Weather (Low, $144K EAL). These account for most of the county's expected annual losses.
How does Grundy County compare to other Iowa counties?
Grundy County ranks #97 of 99 Iowa counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Grundy County had?
FEMA records 15 federal disaster declarations for Grundy County since 1969, most often 8 for severe storm events and 4 for flood events. The most recent was Severe Storms, declared in August 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. Grundy County's $10M EAL is a statistical average, not a guarantee for any specific year or address.