HazardFacts

All states › Missouri › St. Louis County

Natural hazard risk in St. Louis County, Missouri

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

FEMA overall Risk Index rating: Relatively High (score 99.3 of 100)[5]

Expected annual loss (FEMA)
$752.7 million[1]
Federal disaster declarations since 1973
32[2]
NFIP flood claims paid, 1978 to 2026
$264.8 million[3]
Tornadoes recorded, 1950 to 2024
44[4]

FEMA's National Risk Index rates the county Relatively High overall, with a Risk Index score of 99.3 out of 100[5]. The hazards with the highest FEMA scores within the county are heat wave, hail and lightning[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 estimates Expected Annual Loss from all 18 natural hazards at $752.7 million a year for the county[1]. Expected Annual Loss is FEMA's estimate of average yearly loss, and the index is not meant to predict next year's damage[7]. FEMA lists the largest expected losses as heat wave ($253.2 million a year), inland flooding ($240.3 million a year) and earthquake ($140.5 million a year)[8]. FEMA rates Social Vulnerability as Relatively Low (score 31.1), which describes how susceptible social groups are to harm from natural hazards[9]. FEMA rates Community Resilience as Relatively High (score 79.7), which describes a community's ability to prepare for, withstand and recover from hazards[10]. All ratings compare the county with other US counties[7].

Hazards sorted by FEMA hazard-type Risk Index score, highest first
HazardFEMA risk ratingExpected annual loss
Heat WaveVery High$253.2 million[11]
HailVery High$38.0 million[12]
LightningVery High$5.5 million[13]
Cold WaveVery High$40.8 million[14]
Inland FloodingRelatively High$240.3 million[15]
EarthquakeRelatively High$140.5 million[16]
Ice StormVery High$3.8 million[17]
Winter WeatherVery High$1.5 million[18]
TornadoRelatively High$26.3 million[19]
LandslideRelatively Moderate$443,000[20]
Strong WindRelatively High$2.2 million[21]
WildfireVery Low$101,000[22]
HurricaneVery Low$48,000[23]
DroughtVery Low$20,000[24]

Rated Not Applicable by FEMA for this county: avalanche, coastal flooding, tsunami, volcanic activity[25].

Social vulnerability and community resilience

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

FEMA measureRatingScore
Social vulnerabilityRelatively Low31.1[9]
Community resilienceRelatively High79.7[10]

Flooding and flood insurance

FEMA rates inland flooding risk Relatively High compared with other US counties, with Expected Annual Loss of $240.3 million a year[15]. OpenFEMA lists 2,070 residential flood insurance contracts in force as of 2026-08-03[26]. Inside FEMA's mapped Special Flood Hazard Area, 34% of homes are insured[26]. OpenFEMA data show 12,031 NFIP claims for losses from 1978 to 2026, and NFIP paid $264.8 million in total[3]. To learn about a specific address, use FEMA's Flood Map Service Center[27].

Measure Value
Inland Flooding, FEMA risk rating[15] Relatively High, $240.3 million expected loss a year
NFIP residential flood policies in force (2026)[26] 2,070 of 360,986 homes
Homes in FEMA's mapped high-risk flood area (SFHA)[26] 3,470, of which 1,178 insured
NFIP flood claims, 1978 to 2026[3] 12,031 filed, $264.8 million paid

Is a specific address in a flood zone? Only FEMA's flood maps answer that, property by property[27]. This page describes the whole county.

Search an address on the FEMA Flood Map Service Center

Disaster declarations and tornado records

OpenFEMA lists 32 federal disaster declarations for natural hazards that include the county since 1973[2]. By incident type, severe storm accounts for 16 and flood for 10[2]. The most recent listed is DR-4877-MO, declared 2025-06-09[28]. NOAA's tornado database records 44 tornadoes touching the county from 1950 to 2024, and the most recent was on 2024-04-18[4].

Federal disaster declarations for natural hazards that include St. Louis County, since 1973
Incident type Declarations
Severe Storm[2] 16
Flood[2] 10
Severe Ice Storm[2] 3
Hurricane[2] 1
Drought[2] 1
Tornado[2] 1
Most recent declarations
Declaration Incident Declared
DR-4877-MO[28] Severe Storms, Straight-Line Winds, Tornadoes, And Flooding 2025-06-09
DR-4867-MO[28] Severe Storms, Straight-Line Winds, Tornadoes, And Wildfires 2025-05-21
DR-4665-MO[28] Severe Storms And Flooding 2022-08-08
DR-4317-MO[28] Severe Storms, Tornadoes, Straight-Line Winds And Flooding 2017-06-02
DR-4250-MO[28] Severe Storms, Tornadoes, Straight-Line Winds, And Flooding 2016-01-21

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.

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

Winter storms and cold

Before

  • Insulate your home and learn how to keep pipes from freezing.
  • Install and test smoke and carbon monoxide detectors with battery backup.
  • Keep several days of supplies in case the power goes out, including medication and pet needs.
  • Put an emergency kit in your car with jumper cables, sand, blankets, water and snacks, and keep the tank full.

During

  • Under a winter storm warning, find shelter right away.
  • Stay off the roads if you can. If you are stuck in your car, stay inside it.
  • Run generators and grills only outdoors, away from windows, and never heat your home with an oven or stove.

Source: Ready.gov, winter storms and cold

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 St. Louis County at risk of flooding?
FEMA rates inland flooding risk Relatively High compared with other US counties[15]. FEMA's Flood Map Service Center is the place to check a specific address[27].
Does St. Louis County get tornadoes?
NOAA's tornado database records 44 tornadoes touching the county from 1950 to 2024[4]. FEMA rates tornado risk Relatively High compared with other US counties[19].
Is St. Louis County at risk of earthquakes?
FEMA rates earthquake risk Relatively High compared with other US counties[16]. FEMA lists Expected Annual Loss from earthquakes at $140.5 million a year[16].
Is St. Louis County at risk of hurricanes or wildfire?
FEMA rates hurricane risk Very Low compared with other US counties[23]. FEMA also rates wildfire risk Very Low[22].
How many disasters have been declared in St. Louis County?
OpenFEMA lists 32 federal disaster declarations for natural hazards that include the county since 1973[2].

Facts and sources

  1. FEMA National Risk Index (version 1.20, December 2025): Expected Annual Loss from all 18 natural hazards in St. Louis County is $752.7 million a year (Expected Annual Loss rating Relatively High, score 99.4). Of this, buildings account for $373.5 million, injuries and deaths (converted to dollars by FEMA) for... FEMA National Risk Index
  2. OpenFEMA Disaster Declarations Summaries list 32 federal disaster declarations for natural hazards that include St. Louis County since 1973 (24 major disaster, 8 emergency or fire management). By incident type: severe storm 16, flood 10, severe ice storm 3, hurricane 1, drought 1, tornado 1. Biological (such as... OpenFEMA Disaster Declarations
  3. HazardFacts tally of OpenFEMA NFIP Redacted Claims (losses from 1978 to 2026): 12,031 National Flood Insurance Program claims were filed for losses in St. Louis County, 9,937 of them with a payment, and NFIP paid $264.8 million in total (building, contents and increased cost of compliance, in dollars of the year... OpenFEMA NFIP claims
  4. NOAA Storm Prediction Center tornado database (1950 to 2024): 44 recorded tornadoes touched St. Louis County. The strongest were rated F4 (most recent of them on 1967-01-24). 6 were rated F3/EF3 or stronger. The most recent recorded tornado was on 2024-04-18. 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 St. Louis County is Relatively High, with a Risk Index score of 99.3 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 St. Louis County are heat wave (99.8, Very High), hail (99.7, Very High), lightning (99.3, Very High). HazardFacts sorted FEMA's published scores; FEMA's scores compare... 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. HazardFacts sorted FEMA's hazard-type Expected Annual Loss values for St. Louis County (National Risk Index v1.20): the largest are heat wave ($253.2 million a year), inland flooding ($240.3 million a year), earthquake ($140.5 million a year), out of $752.7 million a year from all 18 hazards. FEMA National Risk Index
  9. FEMA National Risk Index (version 1.20, December 2025): Social Vulnerability rating for St. Louis County is Relatively Low (score 31.1). FEMA describes social vulnerability as how susceptible social groups are to the harm natural hazards cause. FEMA National Risk Index
  10. FEMA National Risk Index (version 1.20, December 2025): Community Resilience rating for St. Louis County is Relatively High (score 79.7). FEMA describes community resilience as a community's ability to prepare for, withstand and recover from hazards. FEMA National Risk Index
  11. FEMA National Risk Index (version 1.20, December 2025), heat wave in St. Louis County: Risk Index rating Very High (score 99.8 of 100). Expected Annual Loss $253.2 million a year (rating Very High). Annualized frequency 14.84 event-days per year, from recorded occurrences over a period of record of 18 years. FEMA National Risk Index
  12. FEMA National Risk Index (version 1.20, December 2025), hail in St. Louis County: Risk Index rating Very High (score 99.7 of 100). Expected Annual Loss $38.0 million a year (rating Very High). Annualized frequency 5.26 events per year, from recorded occurrences over a period of record of 37 years. FEMA National Risk Index
  13. FEMA National Risk Index (version 1.20, December 2025), lightning in St. Louis County: Risk Index rating Very High (score 99.3 of 100). Expected Annual Loss $5.5 million a year (rating Very High). Annualized frequency 52.97 events per year, from recorded occurrences over a period of record of 24 years. FEMA National Risk Index
  14. FEMA National Risk Index (version 1.20, December 2025), cold wave in St. Louis County: Risk Index rating Very High (score 99.0 of 100). Expected Annual Loss $40.8 million a year (rating Very High). Annualized frequency 1.74 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), inland flooding in St. Louis County: Risk Index rating Relatively High (score 99.0 of 100). Expected Annual Loss $240.3 million a year (rating Relatively High). Annualized frequency 2.79 event-days per year, from recorded occurrences over a period of record of... FEMA National Risk Index
  16. FEMA National Risk Index (version 1.20, December 2025), earthquake in St. Louis County: Risk Index rating Relatively High (score 99.0 of 100). Expected Annual Loss $140.5 million a year (rating Relatively High). FEMA's modeled annual frequency is 0.0054 events per year. FEMA National Risk Index
  17. FEMA National Risk Index (version 1.20, December 2025), ice storm in St. Louis County: Risk Index rating Very High (score 98.8 of 100). Expected Annual Loss $3.8 million a year (rating Very High). Annualized frequency 1.41 event-days per year, from recorded occurrences over a period of record of 68 years. FEMA National Risk Index
  18. FEMA National Risk Index (version 1.20, December 2025), winter weather in St. Louis County: Risk Index rating Very High (score 98.3 of 100). Expected Annual Loss $1.5 million a year (rating Very High). Annualized frequency 8.74 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), tornado in St. Louis County: Risk Index rating Relatively High (score 98.0 of 100). Expected Annual Loss $26.3 million a year (rating Relatively High). Annualized frequency 0.41 events per year, from recorded occurrences over a period of record of 38 years. FEMA National Risk Index
  20. FEMA National Risk Index (version 1.20, December 2025), landslide in St. Louis County: Risk Index rating Relatively Moderate (score 97.5 of 100). Expected Annual Loss $443,000 a year (rating Relatively Moderate). FEMA National Risk Index
  21. FEMA National Risk Index (version 1.20, December 2025), strong wind in St. Louis County: Risk Index rating Relatively High (score 89.7 of 100). Expected Annual Loss $2.2 million a year (rating Relatively High). Annualized frequency 5.93 events per year, from recorded occurrences over a period of record of 38 years. FEMA National Risk Index
  22. FEMA National Risk Index (version 1.20, December 2025), wildfire in St. Louis County: Risk Index rating Very Low (score 61.7 of 100). Expected Annual Loss $101,000 a year (rating Relatively Low). FEMA's modeled annual frequency is 0.0001 events per year. FEMA National Risk Index
  23. FEMA National Risk Index (version 1.20, December 2025), hurricane in St. Louis County: Risk Index rating Very Low (score 45.0 of 100). Expected Annual Loss $48,000 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... FEMA National Risk Index
  24. FEMA National Risk Index (version 1.20, December 2025), drought in St. Louis County: Risk Index rating Very Low (score 27.7 of 100). Expected Annual Loss $20,000 a year (rating Very Low). Annualized frequency 1.86 event-days per year, from recorded occurrences over a period of record of 22 years. FEMA National Risk Index
  25. FEMA National Risk Index (version 1.20, December 2025) rates these hazards Not Applicable for St. Louis 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... FEMA National Risk Index documentation
  26. NFIP Residential Penetration Rates (OpenFEMA, as of 2026-08-03): 2,070 residential flood insurance contracts were in force in St. Louis County, out of 360,986 residential structures, a penetration rate of 0.6%. Inside FEMA's mapped Special Flood Hazard Area there were 3,470 residential structures and 1,178... OpenFEMA NFIP penetration rates
  27. 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
  28. 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.