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B+Hazard risk
Natural hazards in Grimes · FEMA

Less hazard damage per building is expected in Grimes than in 70% of U.S. towns, mostly from river and rain flooding

On FEMA’s National Risk Index, Grimes gets a B+ for hazard risk: lower expected damage per building than 70% of U.S. towns, #42 of 140 in Iowa. Most of that expected damage is river and rain flooding (69%), then tornadoes (19%). Flood insurance has paid 3 claims here since 2010.

River and rain flooding 69%Tornadoes 19%Strong wind 8%

Graded on FEMA’s expected yearly building damage per dollar of building value (NRI v1.20, December 2025), weighted by where residents live; flood claims are shown, not graded. How hazard risk is graded

less than 70%of U.S. townsLess damageMoreExpected yearly damage per dollar of building, vs. the 21,298 U.S. towns we grade#42 of 140 in Iowa
Hazard risk
B+#42 of 140
in Iowa · lower than 70% of U.S. towns
Main hazard
River and rain flooding
69% of expected building damage
Flood claims
3
paid since 2010 · $28K
Disasters paid out here
7
of 18 declared for Polk County

What stands out about Grimes’ natural hazards

From FEMA’s model and FEMA’s records, below.

Lower expected damage than 70% of U.S. townsFEMA’s model of yearly storm and flood damage per dollar of building.Moved out of harm’s way2 flood-prone properties bought out and cleared with FEMA grants.
By hazard

What Grimes faces

Each hazard’s share of the building damage FEMA expects here, and how its rate compares with the rest of the country.

River and rain flooding

69%of expected building damage
About average · lower than 59% of U.S. census tracts
Recorded about 5 times a year in the area

Tornadoes

19%of expected building damage
Well above average · in the top 9% of U.S. census tracts

Strong wind

8%of expected building damage
Well above average · in the top 6% of U.S. census tracts
Recorded about 6 times a year in the area
Smaller shares here
 Hail Ice storms Earthquakes Winter storms Lightning Hurricanes Wildfire Cold waves Heat waves Landslides
FEMA models no building damage here
Coastal floodingAvalanchesTsunamisVolcanic activity

Shares are of FEMA’s expected building damage, the measure the grade uses; ranks compare each hazard’s building-damage rate with all 85,154 U.S. census tracts. In FEMA’s terms, river and rain flooding is FEMA’s “Inland Flooding” (rivers and streams overflowing their banks, or rain overwhelming drainage). FEMA defines coastal flooding as high or rising tides and storm surge, so surge damage is counted there. Drought isn’t listed: FEMA counts its losses in crops only.

Flood risk changes street by street. Check a specific address on FEMA’s flood map, and ask about flood insurance before you buy.
Hazard risk grade

What’s behind Grimes’ grade

River and rain flooding is 69% of the building damage FEMA expects in Grimes, and Grimes’ rate of river and rain flooding damage is lower than 59% of U.S. census tracts. Tornadoes add 19%, at a rate in the top 9% of U.S. census tracts.

Where Grimes sits
Grimes
Least damageMiddleMost damage

B+ #42 of 140 in Iowa; lower expected damage per building than 70% of U.S. towns (21,298).

Grimes’ residents live in 6 census tracts; FEMA’s figures are combined by where they live.

What drives the damage to buildings
River and rain flooding69%Tornadoes19%Strong wind8%Everything else4%

The typical Iowa town has lower expected damage than 57% of U.S. towns; within the state, Grimes has less expected damage per building than 71% of Iowa towns.

In dollars, FEMA expects about $4.6M a year in losses across Grimes: $3.1M to buildings, the rest to people and crops.

A small-area figure. Grimes covers 6 census tracts, combined by where residents live. FEMA’s model is an average year for today’s buildings, not a record: the claims and disasters below are the record.

How TownRatings grades hazard risk →

Flood insurance claims

Does Grimes flood? Rarely: 3 flood claims since 2010

Every paid claim on a federal flood insurance policy in Grimes, from FEMA’s records: 0.5 per 1,000 homes, fewer than 90% of the 13,809 U.S. towns with a flood insurance record.

Paid flood claims, by year
2010: 2 claims2011: 0 claims2012: 0 claims2013: 0 claims2014: 0 claims2015: 0 claims2016: 0 claims2017: 0 claims2018: 0 claims2019: 0 claims2020: 0 claims2021: 1 claim2022: 0 claims2023: 0 claims2024: 0 claims2025: 0 claims2026: 0 claims20102021
20102026
3
paid claims since 2010
$28K
paid to owners
0
homes flooded more than once
$9K
average claim
of homes in flood zones are insured
of all homes are insured
No community discount

Grimes isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.

Insurance rates: Polk County.
What’s been done with FEMA grants
2flood-prone properties bought out and cleared
Disasters

7 federal disasters brought FEMA money to Grimes

Disasters that paid out in Grimes itself (aid to households or repair grants to the City of Grimes), newest first, with that year’s flood claims.

  1. 2024Severe Storms, Tornadoes, and Flooding16 households applied for aid$20K aid approved
  2. 2020Severe Storms15 households applied for aid$57K to the City of Grimes for repairs
  3. 2018Severe Storms, Tornadoes, Straight-line Winds, and Flooding$35K to the City of Grimes for repairs
  4. 2010Severe Storms, Flooding, and Tornadoes58 households applied for aid$104K aid approved$38K to the City of Grimes for repairs2 flood claims paid that year
  5. 2008Severe Storms, Tornadoes, and Flooding4 households applied for aid$4K aid approved
  6. 2007Severe Winter Storms$18K to the City of Grimes for repairs
Show all 7
  1. 2004Severe Storms, Tornadoes, and Flooding2 households applied for aid$6K aid approved
Disasters declared, by decade
Paid out in GrimesPolk County only

Polk County has had 18 natural disasters declared by the President since 1953, most often severe storms, then floods. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.

Were you here?

Old photos of Grimes after a storm or flood belong in the town’s history. Add one, or share what you remember below.

Add to the Grimes archive →
Next door

Grimes and its neighbors

Grimes is 2nd of the 3 graded towns here, from least expected damage per building to most. Tap a town to see its hazards.

Urbandale: hazard risk B+Johnston: hazard risk AUrbandaleJohnstonGrimes
Lowest fifthSecondMiddleFourthHighest fifth
TownHazard riskMostly (buildings)Flood claims
JohnstonAless damage than 86%river and rain flooding15
GrimesB+less damage than 70%river and rain flooding3
UrbandaleB+less damage than 67%river and rain flooding15

Hazard risk = FEMA’s expected yearly building damage per dollar of building value, vs. the 21,298 U.S. towns we grade; the map is shaded by fifths of the same scale. Flood claims = paid federal flood insurance claims on record.

Be ready

Get ready for what Grimes faces

A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.

When the river rises
  • Turn around at flooded roads: a foot of moving water can carry off a car.
  • Flood insurance usually takes 30 days to start, so buy it before the forecast.
  • Keep papers and medicines up high, in a grab-and-go bag.
More from Ready.gov ↗
Tornado warnings
  • Pick your spot now: the lowest floor, an inside room, no windows.
  • A watch means be ready; a warning means take cover now.
  • Keep shoes and a flashlight by the bed.
More from Ready.gov ↗
High winds
  • Trim dead limbs over the house and driveway.
  • Tie down trash cans and outdoor furniture.
  • Stay clear of downed lines and call the utility.
More from Ready.gov ↗
Before you buy or rent
  • Look up the address on FEMA’s flood map.
  • Ask the seller or landlord whether it has ever flooded, and what flood insurance costs there.
  • Get a flood insurance quote early: policies usually start 30 days after you buy.
When a storm is coming
Forecast and alertsWeather →911, the nearest ERSafety →

Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.

Questions about natural hazards in Grimes

Is Grimes at risk for natural disasters?

On FEMA’s National Risk Index, Grimes has lower expected damage per building than 70% of U.S. towns: B+ for hazard risk, #42 of 140 in Iowa. Most of the expected damage is river and rain flooding (69%) and tornadoes (19%). This is FEMA’s model of an average year for today’s buildings, not a forecast.

Does Grimes flood?

Flood insurance has paid 3 claims in Grimes since 2010, $28K in all, or 0.5 per 1,000 homes, fewer than 90% of U.S. towns with a flood insurance record.

Is Grimes in a flood zone?

Flood zones are drawn street by street, so the answer depends on the address: look it up on FEMA’s flood map. In Polk County, 23% of homes in mapped flood zones carry federal flood insurance, and 0.4% of all homes do.

How much is flood insurance in Grimes?

FEMA’s Community Rating System list shows no discount for Grimes’ flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.

What was the biggest storm in Grimes?

By FEMA money that reached Grimes, Severe Storms, Flooding, and Tornadoes (2010): 58 households applied for aid, $104K approved, and $38K to the City of Grimes for repairs.

Is Grimes at risk from river and rain flooding?

It is the largest share of the building damage FEMA expects here (69%), and Grimes’ rate for it is lower than 59% of U.S. census tracts.

Storm stories

Memories, warnings and help from neighbors in Grimes.

Town Square →
Start the conversation

Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Grimes’ residents lived in the 2020 census; OpenFEMA: NFIP redacted claims, multiple-loss properties, community status book and residential penetration rates, housing assistance (owners and renters), public assistance funded projects, hazard mitigation properties and disaster declarations. Homes: Census ACS 2020–24. Preparedness tips: Ready.gov. FEMA’s model is an average of expected damage, not a forecast. How hazard risk is graded.