Dallas County, Iowa Natural Disaster Risk
FEMA National Risk Index assessment · IA
LowComposite Risk Score
National percentile: 61th
Dallas County faces low composite natural disaster risk (NRI Risk Index score 60.6, 61th national percentile), driven primarily by drought and tornado exposure. Expected annual loss across all 18 hazard types is $40M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Dallas County is low, with a National Risk Index score of 60.6 out of 100 — placing it in the 61st national percentile and below the national average for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Most of Dallas County's expected losses come from drought (extended dry periods that stress water supplies and agriculture) at High risk — $4M in expected annual loss and about 7.79 events per year; tornado (violently rotating columns of air capable of catastrophic local damage) at Medium risk — $10M in expected annual loss and about 0.58 events per year; and hail (ice stones from severe thunderstorms that damage property and crops) at Medium risk — $2M in expected annual loss and about 6.27 events per year. Across all hazards, FEMA estimates $40M in expected annual loss for a population of 100K.
Beyond physical exposure, Dallas 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: Dallas County has received 20 federal disaster declarations since 1965, including 9 for severe storm events and 6 for flood events. The most recent was Severe Storms, Tornadoes, and Flooding (severe storm), declared in May 2024.
Among 99 Iowa counties, Dallas County ranks #16 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Drought | High | 7.79 / yr | $4M |
| Tornado | Medium | 0.58 / yr | $10M |
| Hail | Medium | 6.27 / yr | $2M |
| Heat Wave | Low | 7.05 / yr | $2M |
| Winter Weather | Medium | 14.42 / yr | $256K |
| Ice Storm | Medium | 0.83 / yr | $375K |
| Strong Wind | Medium | 5.86 / yr | $2M |
| Riverine Flood | Low | 4.25 / yr | $17M |
| Landslide | Very Low | 0.11 / yr | $5K |
| Cold Wave | Low | 6.26 / yr | $2M |
| Lightning | Low | 44.48 / yr | $444K |
| Wildfire | Very Low | 0.00 / yr | $51K |
| Earthquake | Very Low | 0.00 / yr | $86K |
| 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
Dallas County has received 20 federal disaster declarations since 1965, most recently Severe Storms, Tornadoes, and Flooding in May 2024. Most frequent causes: Severe Storm (9), Flood (6), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| May 2024 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| August 2020 | Severe Storm | Severe Storms |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| March 2019 | Flood | Severe Storms and Flooding |
| August 2018 | Severe Storm | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| July 2015 | Severe Storm | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| July 2010 | Severe Storm | Severe Storms, Flooding, and Tornadoes |
| March 2010 | Severe Storm | Severe Winter Storm |
| May 2008 | 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 Dallas County?
Dallas County has a composite FEMA National Risk Index score of 60.6 out of 100, placing it in the Low category and the 61th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Dallas County?
The three highest-rated hazards are Drought (High, $4M EAL), Tornado (Medium, $10M EAL), Hail (Medium, $2M EAL). These account for most of the county's expected annual losses.
How does Dallas County compare to other Iowa counties?
Dallas County ranks #16 of 99 Iowa counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Dallas County had?
FEMA records 20 federal disaster declarations for Dallas County since 1965, most often 9 for severe storm events and 6 for flood events. The most recent was Severe Storms, Tornadoes, and Flooding, declared in May 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. Dallas County's $40M EAL is a statistical average, not a guarantee for any specific year or address.