Louisa County, Iowa Natural Disaster Risk
FEMA National Risk Index assessment · IA
Very LowComposite Risk Score
National percentile: 17th
Louisa County faces very low composite natural disaster risk (NRI Risk Index score 17.5, 17th national percentile), driven primarily by drought and strong wind exposure. Expected annual loss across all 18 hazard types is $8M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Louisa County is very low, with a National Risk Index score of 17.5 out of 100 — placing it in the 17th 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.
Most of Louisa County's expected losses come from drought (extended dry periods that stress water supplies and agriculture) at Medium risk — $1M in expected annual loss and about 9.93 events per year; strong wind (damaging straight-line winds outside of tornadoes and hurricanes) at Medium risk — $2M in expected annual loss and about 6.30 events per year; and hail (ice stones from severe thunderstorms that damage property and crops) at Low risk — $648K in expected annual loss and about 4.37 events per year. Across all hazards, FEMA estimates $8M in expected annual loss for a population of 11K.
Beyond physical exposure, Louisa County has a very low social vulnerability rating (how susceptible the population is to harm) and a medium community resilience rating (its capacity to prepare for and recover from disasters). Both measures sit toward the lower end, indicating relatively modest population sensitivity.
The federal record bears this out: Louisa County has received 20 federal disaster declarations since 1965, including 11 for flood events and 6 for severe storm events. The most recent was Covid-19 Pandemic (biological), declared in March 2020.
Among 99 Iowa counties, Louisa County ranks #90 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Drought | Medium | 9.93 / yr | $1M |
| Strong Wind | Medium | 6.30 / yr | $2M |
| Hail | Low | 4.37 / yr | $648K |
| Landslide | Low | 0.10 / yr | $5K |
| Heat Wave | Low | 8.16 / yr | $532K |
| Ice Storm | Low | 0.50 / yr | $105K |
| Wildfire | Very Low | 0.00 / yr | $25K |
| Tornado | Low | 0.37 / yr | $828K |
| Earthquake | Very Low | 0.00 / yr | $99K |
| Lightning | Low | 45.37 / yr | $138K |
| Winter Weather | Very Low | 13.74 / yr | $26K |
| Riverine Flood | Very Low | 2.25 / yr | $3M |
| Cold Wave | Very Low | 5.26 / yr | $293K |
| Hurricane | Very Low | 0.01 / yr | $3K |
| 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
Louisa County has received 20 federal disaster declarations since 1965, most recently Covid-19 Pandemic in March 2020. Most frequent causes: Flood (11), Severe Storm (6), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| March 2019 | Flood | Severe Storms 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 |
| June 2002 | Flood | Severe Storms and Flooding |
| May 2001 | Severe Storm | Severe Storms, Tornadoes and Flooding |
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 Louisa County?
Louisa County has a composite FEMA National Risk Index score of 17.5 out of 100, placing it in the Very Low category and the 17th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Louisa County?
The three highest-rated hazards are Drought (Medium, $1M EAL), Strong Wind (Medium, $2M EAL), Hail (Low, $648K EAL). These account for most of the county's expected annual losses.
How does Louisa County compare to other Iowa counties?
Louisa County ranks #90 of 99 Iowa counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Louisa County had?
FEMA records 20 federal disaster declarations for Louisa County since 1965, most often 11 for flood events and 6 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. Louisa County's $8M EAL is a statistical average, not a guarantee for any specific year or address.