Worth County, Iowa Natural Disaster Risk
FEMA National Risk Index assessment · IA
Very LowComposite Risk Score
National percentile: 10th
Worth County faces very low composite natural disaster risk (NRI Risk Index score 9.9, 10th national percentile), driven primarily by drought and winter weather exposure. Expected annual loss across all 18 hazard types is $7M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Worth County at very low composite risk, with a National Risk Index score of 9.9 out of 100 — placing it in the 10th 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.
The county's risk is driven primarily by drought (extended dry periods that stress water supplies and agriculture) at Medium risk — $2M in expected annual loss and about 22.31 events per year; winter weather (heavy snow, blizzards, and hazardous winter conditions) at Low risk — $64K in expected annual loss and about 19.58 events per year; and cold wave (prolonged spells of dangerously low temperatures) at Low risk — $910K in expected annual loss and about 11.11 events per year. Across all hazards, FEMA estimates $7M in expected annual loss for a population of 7K.
Beyond physical exposure, Worth County has a very low social vulnerability rating (how susceptible the population is to harm) and a 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: Worth County has received 16 federal disaster declarations since 1965, including 7 for severe storm events and 5 for flood events. The most recent was Severe Storms, Flooding, Straight-Line Winds, and Tornadoes (severe storm), declared in June 2024.
Among 99 Iowa counties, Worth County ranks #99 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Drought | Medium | 22.31 / yr | $2M |
| Winter Weather | Low | 19.58 / yr | $64K |
| Cold Wave | Low | 11.11 / yr | $910K |
| Tornado | Low | 0.34 / yr | $1M |
| Hail | Very Low | 4.39 / yr | $171K |
| Strong Wind | Low | 3.67 / yr | $371K |
| Landslide | Very Low | 0.04 / yr | $122 |
| Ice Storm | Very Low | 0.71 / yr | $13K |
| Riverine Flood | Very Low | 1.11 / yr | $2M |
| Heat Wave | Very Low | 3.37 / yr | $24K |
| Earthquake | Very Low | 0.00 / yr | $7K |
| Wildfire | Very Low | 0.00 / yr | $2K |
| Lightning | Very Low | 40.33 / yr | $15K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Worth County has received 16 federal disaster declarations since 1965, most recently Severe Storms, Flooding, Straight-Line Winds, and Tornadoes in June 2024. Most frequent causes: Severe Storm (7), Flood (5), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| June 2024 | Severe Storm | Severe Storms, Flooding, Straight-Line Winds, and Tornadoes |
| February 2022 | Severe Storm | Severe Storms, Straight-Line Winds, and Tornadoes |
| 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 |
Showing the 10 most recent of 16 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Worth County?
Worth County has a composite FEMA National Risk Index score of 9.9 out of 100, placing it in the Very Low category and the 10th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Worth County?
The three highest-rated hazards are Drought (Medium, $2M EAL), Winter Weather (Low, $64K EAL), Cold Wave (Low, $910K EAL). These account for most of the county's expected annual losses.
How does Worth County compare to other Iowa counties?
Worth County ranks #99 of 99 Iowa counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Worth County had?
FEMA records 16 federal disaster declarations for Worth County since 1965, most often 7 for severe storm events and 5 for flood events. The most recent was Severe Storms, Flooding, Straight-Line Winds, and Tornadoes, declared in June 2024.
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. Worth County's $7M EAL is a statistical average, not a guarantee for any specific year or address.