Hamilton County, Ohio Natural Disaster Risk
FEMA National Risk Index assessment · OH
HighComposite Risk Score
National percentile: 96th
Hamilton County faces high composite natural disaster risk (NRI Risk Index score 96.3, 96th national percentile), driven primarily by tornado and heat wave exposure. Expected annual loss across all 18 hazard types is $221M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Hamilton County at high composite risk, with a National Risk Index score of 96.3 out of 100 — placing it in the 96th national percentile and in the upper tier of natural-disaster risk nationally. 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 tornado (violently rotating columns of air capable of catastrophic local damage) at Very High risk — $53M in expected annual loss and about 0.27 events per year; heat wave (prolonged periods of extreme heat that threaten health and infrastructure) at High risk — $25M in expected annual loss and about 6.47 events per year; and cold wave (prolonged spells of dangerously low temperatures) at High risk — $16M in expected annual loss and about 2.21 events per year. Across all hazards, FEMA estimates $221M in expected annual loss for a population of 831K.
Beyond physical exposure, Hamilton County has a medium 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: Hamilton County has received 18 federal disaster declarations since 1968, including 7 for severe storm events and 4 for flood events. The most recent was Covid-19 Pandemic (biological), declared in March 2020.
Among 88 Ohio counties, Hamilton County ranks #3 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Tornado | Very High | 0.27 / yr | $53M |
| Heat Wave | High | 6.47 / yr | $25M |
| Cold Wave | High | 2.21 / yr | $16M |
| Strong Wind | High | 3.28 / yr | $4M |
| Riverine Flood | High | 5.07 / yr | $109M |
| Lightning | Very High | 50.24 / yr | $2M |
| Landslide | Medium | 0.45 / yr | $142K |
| Hail | Medium | 3.46 / yr | $2M |
| Winter Weather | High | 11.05 / yr | $538K |
| Earthquake | Medium | 0.00 / yr | $8M |
| Ice Storm | High | 0.97 / yr | $658K |
| Wildfire | Very Low | 0.00 / yr | $39K |
| Hurricane | Very Low | 0.01 / yr | $26K |
| Drought | Low | 2.28 / yr | $31K |
| 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
Hamilton County has received 18 federal disaster declarations since 1968, most recently Covid-19 Pandemic in March 2020. Most frequent causes: Severe Storm (7), Flood (4), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| April 2018 | Flood | Severe Storms, Landslides, and Mudslides |
| June 2012 | Severe Storm | Severe Storms |
| July 2011 | Severe Storm | Severe Storms and Flooding |
| October 2008 | Severe Storm | Severe Wind Storm Associated with Tropical Depression Ike |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| January 2005 | Snowstorm | Snow |
| September 2004 | Severe Storm | Severe Storms and Flooding |
| August 2001 | Severe Storm | Severe Storms and Flooding |
Showing the 10 most recent of 18 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Hamilton County?
Hamilton County has a composite FEMA National Risk Index score of 96.3 out of 100, placing it in the High category and the 96th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Hamilton County?
The three highest-rated hazards are Tornado (Very High, $53M EAL), Heat Wave (High, $25M EAL), Cold Wave (High, $16M EAL). These account for most of the county's expected annual losses.
How does Hamilton County compare to other Ohio counties?
Hamilton County ranks #3 of 88 Ohio counties for overall natural disaster risk, with a high rating.
How many federally declared disasters has Hamilton County had?
FEMA records 18 federal disaster declarations for Hamilton County since 1968, most often 7 for severe storm events and 4 for flood 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. Hamilton County's $221M EAL is a statistical average, not a guarantee for any specific year or address.