Linn County, Iowa Natural Disaster Risk
FEMA National Risk Index assessment · IA
MediumComposite Risk Score
National percentile: 87th
Linn County faces medium composite natural disaster risk (NRI Risk Index score 86.7, 87th national percentile), driven primarily by strong wind and hail exposure. Expected annual loss across all 18 hazard types is $79M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Linn County carries a medium composite natural disaster risk, with a National Risk Index score of 86.7 out of 100 — placing it in the 87th national percentile and near the national midpoint 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 strong wind (damaging straight-line winds outside of tornadoes and hurricanes) at Very High risk — $8M in expected annual loss and about 6.10 events per year; hail (ice stones from severe thunderstorms that damage property and crops) at High risk — $7M in expected annual loss and about 4.66 events per year; and tornado (violently rotating columns of air capable of catastrophic local damage) at High risk — $16M in expected annual loss and about 0.68 events per year. Across all hazards, FEMA estimates $79M in expected annual loss for a population of 230K.
Beyond physical exposure, Linn 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: Linn County has received 23 federal disaster declarations since 1965, including 11 for flood events and 8 for severe storm events. The most recent was Severe Storms (severe storm), declared in August 2020.
Among 99 Iowa counties, Linn County ranks #3 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Strong Wind | Very High | 6.10 / yr | $8M |
| Hail | High | 4.66 / yr | $7M |
| Tornado | High | 0.68 / yr | $16M |
| Winter Weather | High | 16.58 / yr | $787K |
| Drought | Medium | 12.99 / yr | $2M |
| Riverine Flood | Medium | 2.21 / yr | $36M |
| Ice Storm | High | 0.31 / yr | $805K |
| Lightning | High | 42.84 / yr | $1M |
| Cold Wave | Medium | 7.89 / yr | $6M |
| Heat Wave | Low | 5.95 / yr | $1M |
| Landslide | Low | 0.14 / yr | $6K |
| Earthquake | Very Low | 0.00 / yr | $498K |
| Wildfire | Very Low | 0.00 / yr | $49K |
| Hurricane | Very Low | 0.01 / yr | $5K |
| 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
Linn County has received 23 federal disaster declarations since 1965, most recently Severe Storms in August 2020. Most frequent causes: Flood (11), Severe Storm (8), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| August 2020 | Severe Storm | Severe Storms |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| October 2016 | Flood | Severe Storms and Flooding |
| August 2014 | Severe Storm | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| July 2013 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| May 2008 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| January 2008 | Severe Ice Storm | Severe Winter Storm |
| March 2007 | Severe Storm | Severe Winter Storms |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
Showing the 10 most recent of 23 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Linn County?
Linn County has a composite FEMA National Risk Index score of 86.7 out of 100, placing it in the Medium category and the 87th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Linn County?
The three highest-rated hazards are Strong Wind (Very High, $8M EAL), Hail (High, $7M EAL), Tornado (High, $16M EAL). These account for most of the county's expected annual losses.
How does Linn County compare to other Iowa counties?
Linn County ranks #3 of 99 Iowa counties for overall natural disaster risk, with a medium rating.
How many federally declared disasters has Linn County had?
FEMA records 23 federal disaster declarations for Linn County since 1965, most often 11 for flood events and 8 for severe storm 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. Linn County's $79M EAL is a statistical average, not a guarantee for any specific year or address.