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Natural hazard risk in Polk County, Iowa

Updated October 30, 2026. Based on FEMA, NOAA and OpenFEMA data. Published by Humblebee.

FEMA overall Risk Index rating: Relatively Moderate (score 91.9 of 100)[5]

Expected annual loss (FEMA)
$137.6 million[1]
Federal disaster declarations since 1965
19[2]
NFIP flood claims paid, 1978 to 2026
$38.5 million[3]
Tornadoes recorded, 1950 to 2024
70[4]

FEMA's National Risk Index (version 1.20, December 2025) rates overall natural hazard risk in Polk County, Iowa, as Relatively Moderate compared with other US counties, with a Risk Index score of 91.9 out of 100[5]. Within the county, the hazards with the highest FEMA scores are strong wind, rated Very High, and tornado and hail, both rated Relatively High[6].

FEMA risk ratings for each hazard

Ratings and expected losses from the FEMA National Risk Index. Each rating compares this county with all US counties for that hazard, from Very Low to Very High. They are planning estimates, not predictions, and they do not describe any single property.

FEMA's National Risk Index estimates Expected Annual Loss from all natural hazards in Polk County at $137.6 million a year, rated Relatively Moderate[1]. This is FEMA's estimate of average yearly economic loss, not money anyone paid, and it does not predict next year's losses[7]. Inland flooding carries the largest hazard estimate at $60.6 million a year[8], followed by tornado at $30.9 million a year[9] and strong wind at $11.5 million a year[10]. FEMA rates social vulnerability in Polk County Very Low (score 16.9)[11] and community resilience Very High (score 91.1)[12], which in FEMA's terms means social groups here are less susceptible to hazard harm and the community is better able to prepare for, withstand and recover from hazards than in most US counties[11][12].

Hazards sorted by FEMA hazard-type Risk Index score, highest first
HazardFEMA risk ratingExpected annual loss
Strong WindVery High$11.5 million[10]
TornadoRelatively High$30.9 million[9]
HailRelatively High$7.4 million[13]
Heat WaveRelatively High$10.7 million[14]
DroughtRelatively High$3.1 million[15]
Inland FloodingRelatively Moderate$60.6 million[8]
Ice StormRelatively High$1.4 million[16]
Cold WaveRelatively High$9.8 million[17]
Winter WeatherRelatively High$506,000[18]
LightningRelatively Moderate$816,000[19]
LandslideRelatively Low$6,139[20]
EarthquakeRelatively Low$820,000[21]
WildfireVery Low$91,000[22]
HurricaneVery Low$14,000[23]

Rated Not Applicable by FEMA for this county: avalanche, coastal flooding, tsunami, volcanic activity[24].

Social vulnerability and community resilience

FEMA uses these two ratings to scale expected losses into the Risk Index.

FEMA measureRatingScore
Social vulnerabilityVery Low16.9[11]
Community resilienceVery High91.1[12]

Flooding and flood insurance

FEMA rates inland flooding risk in Polk County Relatively Moderate (score 92.1 of 100), with an Expected Annual Loss rated Relatively High[8]. OpenFEMA data show 670 residential flood insurance contracts in force as of 2026-08-03, a penetration rate of 0.4% of residential structures, and 22.8% inside FEMA's mapped Special Flood Hazard Area[25]. A HazardFacts tally of OpenFEMA records counts 1,550 NFIP claims for losses from 1978 to 2026, with $38.5 million paid in total, and 1993 had the most paid claims (386)[3]. To check the flood zone of an address, use FEMA's Flood Map Service Center or ask the local floodplain manager[26].

Measure Value
Inland Flooding, FEMA risk rating[8] Relatively Moderate, $60.6 million expected loss a year
NFIP residential flood policies in force (2026)[25] 670 of 163,854 homes
Homes in FEMA's mapped high-risk flood area (SFHA)[25] 1,607, of which 366 insured
NFIP flood claims, 1978 to 2026[3] 1,550 filed, $38.5 million paid

Is a specific address in a flood zone? Only FEMA's flood maps answer that, property by property[26]. This page describes the whole county.

Search an address on the FEMA Flood Map Service Center

Disaster declarations and tornado records

OpenFEMA lists 19 federal disaster declarations for natural hazards that include Polk County since 1965, including 8 for flood and 8 for severe storm[2]. The most recent is DR-4942-IA, Severe Storms And Flooding, declared 2026-09-01[27]. NOAA's Storm Prediction Center tornado database records 70 tornadoes that touched Polk County from 1950 to 2024, and the strongest were rated EF4, most recently on 2022-03-05[4].

Federal disaster declarations for natural hazards that include Polk County, since 1965
Incident type Declarations
Flood[2] 8
Severe Storm[2] 8
Snowstorm[2] 1
Tornado[2] 1
Hurricane[2] 1
Most recent declarations
Declaration Incident Declared
DR-4942-IA[27] Severe Storms And Flooding 2026-09-01
DR-4784-IA[27] Severe Storms, Tornadoes, And Flooding 2024-05-24
DR-4779-IA[27] Severe Storms And Tornadoes 2024-05-14
DR-4557-IA[27] Severe Storms 2020-08-17
DR-4421-IA[27] Severe Storms And Flooding 2019-03-23

How to prepare

Steps from Ready.gov, FEMA's preparedness site, for the hazards with the highest FEMA ratings here. Follow instructions from local officials and the National Weather Service when a warning is issued.

Tornadoes

Before

  • Learn the warning signs: a rotating funnel cloud, an approaching cloud of debris or a loud roar like a freight train.
  • Sign up for community warning systems and learn what your local sirens sound like.
  • Pick a safe spot, such as a safe room built to FEMA criteria or an ICC 500 storm shelter, and practice getting there.
  • Include your pets in the household emergency plan.
  • Keep supplies, food, water and medication in case you have to stay home for a long time.

During

  • Go right away to the safe place you picked in advance.
  • Protect your head and neck with your arms and stay away from windows, doors and outside walls.
  • No place in a car is fully safe. If you can get lower than the road, leave the car and lie down there.

Source: Ready.gov, tornadoes

Extreme heat

Before

  • Learn the signs of heat illness and how to respond.
  • Do not rely on a fan as your main way to stay cool. Fans do not lower body temperature.
  • Find cool public places, such as libraries or malls, or ask your local health department.
  • Keep heat out with window shades, weather stripping and insulation.
  • If you cannot afford cooling costs, contact LIHEAP for help.

During

  • Never leave a person or an animal in a parked car in warm weather.
  • If your home has no air conditioning, go to a cooling center.
  • Wear light, loose clothing, drink plenty of fluids and avoid hard outdoor work in the middle of the day.

Source: Ready.gov, extreme heat

Floods

Before

  • Check your flood risk with FEMA's Flood Map Service Center, and remember that floods do not follow map lines.
  • Sign up for your community's warning system. NOAA Weather Radio also broadcasts alerts.
  • Buy flood insurance through the NFIP well before a disaster. Homeowners policies do not cover flooding, and a new policy typically takes up to 30 days to go into effect.
  • Make a household plan with evacuation routes, shelter locations and what to do in a flash flood.
  • Keep important documents in a waterproof container and make password-protected digital copies.

During

  • If you are told to evacuate, leave right away and never drive around barricades.
  • Do not walk, swim or drive through floodwater. Six inches of moving water can knock you down.
  • If you are trapped in a building, go to the highest level, but do not climb into a closed attic.

Source: Ready.gov, floods

Questions people ask

Is Polk County, Iowa at risk of flooding?
FEMA rates inland flooding risk in Polk County Relatively Moderate compared with other US counties, with an Expected Annual Loss of $60.6 million a year[8]. OpenFEMA lists 8 flood disaster declarations that include the county since 1965[2].
How often do tornadoes hit Polk County, Iowa?
NOAA's tornado database records 70 tornadoes that touched Polk County from 1950 to 2024, with the most recent on 2024-07-15[4]. FEMA rates tornado risk Relatively High compared with other US counties, with an annualized frequency of 0.59 events per year[9].
Is Polk County, Iowa at risk of earthquakes or wildfire?
FEMA rates earthquake risk in Polk County Relatively Low (score 66.7 of 100)[21] and wildfire risk Very Low (score 57.6 of 100)[22], compared with other US counties. FEMA notes a hazard can still cause damage where a rating is low[7].
How many disasters have been declared in Polk County, Iowa?
OpenFEMA lists 19 federal disaster declarations for natural hazards that include Polk County since 1965, 18 of them major disaster declarations[2].
How do I check if a home in Polk County is in a flood zone?
Look up the address on FEMA's Flood Map Service Center or ask the local floodplain manager[26]. County-level ratings do not tell you the flood zone of a single address[26].

Facts and sources

  1. FEMA National Risk Index (version 1.20, December 2025): Expected Annual Loss from all 18 natural hazards in Polk County is $137.6 million a year (Expected Annual Loss rating Relatively Moderate, score 93.5). Of this, buildings account for $87.8 million, injuries and deaths (converted to dollars by FEMA) for $45.1... FEMA National Risk Index
  2. OpenFEMA Disaster Declarations Summaries list 19 federal disaster declarations for natural hazards that include Polk County since 1965 (18 major disaster, 1 emergency or fire management). By incident type: flood 8, severe storm 8, snowstorm 1, tornado 1, hurricane 1. Biological (such as COVID-19) and other... OpenFEMA Disaster Declarations
  3. HazardFacts tally of OpenFEMA NFIP Redacted Claims (losses from 1978 to 2026): 1,550 National Flood Insurance Program claims were filed for losses in Polk County, 1,236 of them with a payment, and NFIP paid $38.5 million in total (building, contents and increased cost of compliance, in dollars of the year paid).... OpenFEMA NFIP claims
  4. NOAA Storm Prediction Center tornado database (1950 to 2024): 70 recorded tornadoes touched Polk County. The strongest were rated EF4 (most recent of them on 2022-03-05). 3 were rated F3/EF3 or stronger. The most recent recorded tornado was on 2024-07-15. Ratings used the Fujita scale until early 2007 and the... NOAA Storm Prediction Center
  5. FEMA National Risk Index (version 1.20, December 2025): the overall natural hazard Risk Index rating for Polk County is Relatively Moderate, with a Risk Index score of 91.9 out of 100. The score is the county's percentile rank among all US counties. FEMA National Risk Index
  6. Among the 18 hazards in the FEMA National Risk Index (version 1.20, December 2025), the hazards with the highest hazard-type Risk Index scores for Polk County are strong wind (99.2, Very High), tornado (98.1, Relatively High), hail (97.9, Relatively High). HazardFacts sorted FEMA's published scores; FEMA's scores... FEMA National Risk Index
  7. FEMA's National Risk Index FAQ (December 2025): Expected Annual Loss is FEMA's estimate of the average economic loss in dollars from natural hazards each year. The index is not meant to predict how much damage a community will have in the next year, and a hazard can still cause damage where a rating is low. Scores... FEMA National Risk Index documentation
  8. FEMA National Risk Index (version 1.20, December 2025), inland flooding in Polk County: Risk Index rating Relatively Moderate (score 92.1 of 100). Expected Annual Loss $60.6 million a year (rating Relatively High). Annualized frequency 5.07 event-days per year, from recorded occurrences over a period of record of... FEMA National Risk Index
  9. FEMA National Risk Index (version 1.20, December 2025), tornado in Polk County: Risk Index rating Relatively High (score 98.1 of 100). Expected Annual Loss $30.9 million a year (rating Relatively High). Annualized frequency 0.59 events per year, from recorded occurrences over a period of record of 38 years. FEMA National Risk Index
  10. FEMA National Risk Index (version 1.20, December 2025), strong wind in Polk County: Risk Index rating Very High (score 99.2 of 100). Expected Annual Loss $11.5 million a year (rating Very High). Annualized frequency 6.01 events per year, from recorded occurrences over a period of record of 38 years. FEMA National Risk Index
  11. FEMA National Risk Index (version 1.20, December 2025): Social Vulnerability rating for Polk County is Very Low (score 16.9). FEMA describes social vulnerability as how susceptible social groups are to the harm natural hazards cause. FEMA National Risk Index
  12. FEMA National Risk Index (version 1.20, December 2025): Community Resilience rating for Polk County is Very High (score 91.1). FEMA describes community resilience as a community's ability to prepare for, withstand and recover from hazards. FEMA National Risk Index
  13. FEMA National Risk Index (version 1.20, December 2025), hail in Polk County: Risk Index rating Relatively High (score 97.9 of 100). Expected Annual Loss $7.4 million a year (rating Relatively High). Annualized frequency 6.13 events per year, from recorded occurrences over a period of record of 37 years. FEMA National Risk Index
  14. FEMA National Risk Index (version 1.20, December 2025), heat wave in Polk County: Risk Index rating Relatively High (score 96.6 of 100). Expected Annual Loss $10.7 million a year (rating Relatively High). Annualized frequency 7.32 event-days per year, from recorded occurrences over a period of record of 18 years. FEMA National Risk Index
  15. FEMA National Risk Index (version 1.20, December 2025), drought in Polk County: Risk Index rating Relatively High (score 94.8 of 100). Expected Annual Loss $3.1 million a year (rating Relatively High). Annualized frequency 6.46 event-days per year, from recorded occurrences over a period of record of 22 years. FEMA National Risk Index
  16. FEMA National Risk Index (version 1.20, December 2025), ice storm in Polk County: Risk Index rating Relatively High (score 91.7 of 100). Expected Annual Loss $1.4 million a year (rating Relatively High). Annualized frequency 0.93 event-days per year, from recorded occurrences over a period of record of 68 years. FEMA National Risk Index
  17. FEMA National Risk Index (version 1.20, December 2025), cold wave in Polk County: Risk Index rating Relatively High (score 91.2 of 100). Expected Annual Loss $9.8 million a year (rating Relatively High). Annualized frequency 6 event-days per year, from recorded occurrences over a period of record of 18 years. FEMA National Risk Index
  18. FEMA National Risk Index (version 1.20, December 2025), winter weather in Polk County: Risk Index rating Relatively High (score 90.2 of 100). Expected Annual Loss $506,000 a year (rating Relatively High). Annualized frequency 14.11 events per year, from recorded occurrences over a period of record of 18 years. FEMA National Risk Index
  19. FEMA National Risk Index (version 1.20, December 2025), lightning in Polk County: Risk Index rating Relatively Moderate (score 78.0 of 100). Expected Annual Loss $816,000 a year (rating Relatively Moderate). Annualized frequency 44.35 events per year, from recorded occurrences over a period of record of 24 years. FEMA National Risk Index
  20. FEMA National Risk Index (version 1.20, December 2025), landslide in Polk County: Risk Index rating Relatively Low (score 68.3 of 100). Expected Annual Loss $6,139 a year (rating Very Low). FEMA National Risk Index
  21. FEMA National Risk Index (version 1.20, December 2025), earthquake in Polk County: Risk Index rating Relatively Low (score 66.7 of 100). Expected Annual Loss $820,000 a year (rating Relatively Low). FEMA's modeled annual frequency is 0.0006 events per year. FEMA National Risk Index
  22. FEMA National Risk Index (version 1.20, December 2025), wildfire in Polk County: Risk Index rating Very Low (score 57.6 of 100). Expected Annual Loss $91,000 a year (rating Relatively Low). FEMA's modeled annual frequency is 0.0003 events per year. FEMA National Risk Index
  23. FEMA National Risk Index (version 1.20, December 2025), hurricane in Polk County: Risk Index rating Very Low (score 27.4 of 100). Expected Annual Loss $14,000 a year (rating Very Low). Annualized frequency 0.01 events per year, from recorded occurrences over a period of record of 172 years for the Atlantic Basin... FEMA National Risk Index
  24. FEMA National Risk Index (version 1.20, December 2025) rates these hazards Not Applicable for Polk County: avalanche, coastal flooding, tsunami, volcanic activity. FEMA uses Not Applicable when its source data has no historical record of the hazard in the community and the hazard is not considered geographically... FEMA National Risk Index documentation
  25. NFIP Residential Penetration Rates (OpenFEMA, as of 2026-08-03): 670 residential flood insurance contracts were in force in Polk County, out of 163,854 residential structures, a penetration rate of 0.4%. Inside FEMA's mapped Special Flood Hazard Area there were 1,607 residential structures and 366 contracts, a rate... OpenFEMA NFIP penetration rates
  26. FEMA's Flood Map Service Center is the official public source for flood maps (Flood Insurance Rate Maps) produced under the National Flood Insurance Program. Flood zones apply to specific properties: look up an address there or ask the local floodplain manager. County-level ratings do not tell you the flood zone of... FEMA Flood Map Service Center
  27. Most recent federal disaster declarations for natural hazards (table on this page). OpenFEMA Disaster Declarations

FEMA's National Risk Index compares each county with all other US counties. Ratings are relative (Very Low to Very High), not a measure of safety. Never call a place safe, unsafe, good or bad to live in. Risk Index and Expected Annual Loss values are FEMA estimates for planning. They do not predict next year's losses and do not apply to a single property. Flood zones are set by FEMA flood maps for specific properties. County ratings and flood insurance counts do not tell anyone whether an address is in a flood zone. Disaster declaration, NFIP and tornado counts are records of the past for this county only. Do not compare with other counties unless a fact does.

Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties, v1.20 (December 2025). Retrieved from fema.maps.arcgis.com on October 30, 2026. This product uses the Federal Emergency Management Agency's National Risk Index dataset API or downloadable datasets but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s). This product uses the FEMA OpenFEMA API, but is not endorsed by FEMA.