Lyon County, IA
FEMA National Risk Index scores, disaster declarations & hazard data
Lyon County has experienced 16 federally declared disasters since 1965, most recently Severe Storms, Flooding, Straight-Line Winds, And Tornadoes in 2024. Its overall natural hazard risk is rated Very Low — among the lowest-risk counties in the country.
Lyon County's highest-rated hazards are hail, drought, and winter weather, with its top risk rated "Relatively Moderate" by FEMA's National Risk Index. Recorded storm events have decreased 22% over the past five years compared to the prior five-year period. Community vulnerability is relatively low (3rd percentile nationally), indicating stronger recovery capacity than most US counties.
Past disasters & FEMA designations
A federal disaster declaration officially designates a county for FEMA disaster assistance. Lyon County has been designated in 16 declarations since 1965, covering 5 disaster types including severe storm (6), flood (6), biological (2).
| Year | Type | Event name |
|---|---|---|
| 2024 | Severe Storm | Severe Storms, Flooding, Straight-Line Winds, And Tornadoes |
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 |
| 2019 | Flood | Severe Storms And Flooding |
| 2018 | Severe Storm | Severe Storms, Tornadoes, Straight-Line Winds, And Flooding |
| 2014 | Flood | Severe Storms, Tornadoes, Straight-Line Winds, And Flooding |
| 2013 | Severe Storm | Severe Winter Storm |
| 2013 | Severe Storm | Severe Storms, Tornadoes, And Flooding |
| 2010 | Severe Storm | Severe Storms, Flooding, And Tornadoes |
| 2008 | Severe Storm | Severe Storms, Tornadoes, And Flooding |
Showing the 10 most recent of 16 total declarations since 1965.
Source: FEMA OpenFEMA Disaster Declarations Summaries. A single disaster can produce more than one record per county. Data current through September 2026.
Risk by hazard type
| Hazard | Risk rating | Risk score | Recorded events | Deaths | Prop. damage |
|---|---|---|---|---|---|
| Wildfire | Very Low | 28.4 | 0 | 0 | — |
| Inland Flooding | Very Low | 19.6 | 62 | 0 | $15.2M |
| Coastal Flooding | Not Applicable | — | 0 | 0 | — |
| Earthquake | Very Low | 7.5 | — | — | — |
| Heat Wave | Very Low | 29.9 | 19 | 0 | — |
| Tornado | Relatively Low | 45.9 | 6 | 0 | $200K |
| Hurricane | Not Applicable | — | 0 | 0 | — |
| Hail | Relatively Moderate | 89.4 | 32 | 0 | $300K |
| Strong Wind | Relatively Low | 18.6 | 0 | 0 | — |
| Winter Weather | Relatively Moderate | 71.1 | 0 | 0 | — |
| Ice Storm | Relatively Moderate | 67.9 | — | — | — |
| Cold Wave | Relatively Low | 41.8 | — | — | — |
| Lightning | Very Low | 9.2 | 0 | 0 | — |
| Drought | Relatively Moderate | 72 | 0 | 0 | — |
| Landslide | Very Low | 33.4 | 0 | 0 | — |
| Avalanche | Not Applicable | — | — | — | — |
| Tsunami | Not Applicable | — | — | — | — |
| Volcanic Activity | Not Applicable | — | — | — | — |
Scores are 0–100 percentiles relative to all US counties — higher means more exposed, not that a disaster is likely this year. Event counts: NOAA Storm Events 2016–2026; earthquake counts from USGS ComCat (M3.0+, 1996–2026). See the methodology page for details.
Community vulnerability
Lyon County ranks in the 3rd percentile (Very low) for community vulnerability — a measure of how hard disaster impacts tend to hit residents. Higher vulnerability means more displacement, worse health outcomes, and slower recovery after a disaster.
| SVI theme | Percentile | Vulnerability level |
|---|---|---|
| Overall | 3rd | Very low |
| Socioeconomic status | 1st | Very low |
| Household characteristics | 30th | Low |
| Racial & ethnic minority status | 7th | Very low |
| Housing type & transportation | 9th | Very low |
Source: CDC/ATSDR Social Vulnerability Index 2022. Percentiles compare counties nationally — higher means more vulnerable relative to other counties. See CDC SVI for full methodology.
Future risk outlook
| Wildfire metric | National percentile | Level |
|---|---|---|
| Burn probability | 23rd | Relatively Low |
| Risk to homes | 27th | Relatively Low |
| Buildings in direct exposure zone | 36.3% | — |
NOAA tracked 119 weather events in this county over 2016–2025: 67 in 2016–20 vs 52 in 2021–25 (-22% — frequency decreasing).
Wildfire: USDA Forest Service Wildfire Risk to Communities (RDS-2020-0016-2) — modeled values, not annual forecasts. See wildfirerisk.org. Inland flood and heat projections pending data availability; coastal sea-level projections are available for select coastal counties below — see the data page.
Nearby counties
Frequently asked questions
What natural hazards pose the greatest risk in Lyon County?
According to the FEMA National Risk Index, the highest-risk hazards in Lyon County, Iowa are hail, drought, and winter weather. The county's overall natural hazard risk is rated Very Low — among the lowest-risk counties in the country.
Has Lyon County received federal disaster declarations?
Yes. Lyon County has received 16 federal disaster declarations since 1965, including declarations in 2024. The most common disaster type on record is severe storm (6 declarations).
Has Lyon County had any FEMA disaster declarations in 2024, 2025, or 2026?
Yes. Recent federal disaster declarations for Lyon County include Severe Storms, Flooding, Straight-Line Winds, And Tornadoes (2024). See the declarations table above for the full history since 1965.
How does Lyon County's natural hazard risk compare to nearby counties?
Among neighboring counties, Minnehaha County, SD has the highest overall natural hazard risk (Relatively Moderate) and Rock County, MN has the lowest (Very Low). Lyon County is rated Very Low overall.
How is Lyon County's composite disaster risk index calculated?
Lyon County's composite disaster risk index — officially FEMA's National Risk Index (NRI) — scores every US county on a 0–100 percentile scale across 18 natural hazard types, factoring in expected annual loss, social vulnerability, and community resilience. Lyon County's composite score of 19 means its overall natural hazard risk is higher than 19% of US counties.