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Natural hazard risk in St. Clair County, Illinois

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

FEMA overall Risk Index rating: Relatively High (score 94.9 of 100)[5]

Expected annual loss (FEMA)
$174.6 million[1]
Federal disaster declarations since 1968
17[2]
NFIP flood claims paid, 1978 to 2026
$7.8 million[3]
Tornadoes recorded, 1950 to 2024
54[4]

FEMA rates the overall natural hazard risk for St. Clair County, Illinois as Relatively High compared with other US counties, with a Risk Index score of 94.9 out of 100[5]. The hazards with the highest FEMA scores in this county are heat wave, earthquake and hail[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 (version 1.20, December 2025) estimates Expected Annual Loss from all 18 natural hazards at $174.6 million a year[1]. This is a FEMA estimate of average yearly loss, not money anyone paid[7]. FEMA's largest hazard-type loss values are inland flooding at $71.7 million a year, earthquake at $50.8 million a year and heat wave at $15.1 million a year[8]. FEMA rates social vulnerability as Relatively Low, with a score of 37.8[9]. That rating describes how susceptible social groups are to harm from natural hazards[9]. FEMA rates community resilience as Relatively High, with a score of 74.9[10]. That rating describes a community's ability to prepare for, withstand and recover from hazards[10].

Hazards sorted by FEMA hazard-type Risk Index score, highest first
HazardFEMA risk ratingExpected annual loss
Heat WaveRelatively High$15.1 million[11]
EarthquakeRelatively Moderate$50.8 million[12]
HailRelatively High$5.1 million[13]
Cold WaveRelatively High$14.8 million[14]
TornadoRelatively High$13.0 million[15]
Inland FloodingRelatively High$71.7 million[16]
LightningRelatively High$1.6 million[17]
Ice StormRelatively High$1.0 million[18]
Winter WeatherRelatively High$333,000[19]
LandslideRelatively Low$28,000[20]
DroughtRelatively Low$314,000[21]
Strong WindRelatively Moderate$627,000[22]
HurricaneVery Low$21,000[23]
WildfireVery Low$5,162[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 Low37.8[9]
Community resilienceRelatively High74.9[10]

Flooding and flood insurance

FEMA rates inland flooding risk as Relatively High in St. Clair County, with a score of 94.4 out of 100[16]. OpenFEMA data as of 2026-08-03 list 1,007 residential flood insurance contracts in force, out of 101,953 residential structures[26]. HazardFacts counted 1,469 NFIP claims for losses in the county from 1978 to 2026, and NFIP paid $7.8 million in total[3]. The years with the most paid claims were 1993 (240), 1996 (150) and 1995 (90)[3]. To check the flood zone of an address, use FEMA's Flood Map Service Center[27].

Measure Value
Inland Flooding, FEMA risk rating[16] Relatively High, $71.7 million expected loss a year
NFIP residential flood policies in force (2026)[26] 1,007 of 101,953 homes
NFIP flood claims, 1978 to 2026[3] 1,469 filed, $7.8 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 17 federal disaster declarations for natural hazards that include this county since 1968[2]. By incident type, flood accounts for 8, severe storm for 5, tornado for 2, hurricane for 1 and severe ice storm for 1[2]. The most recent declaration listed is DR-4819-IL, declared 2024-09-20[28]. NOAA's tornado database records 54 tornadoes that touched the county from 1950 to 2024[4]. The strongest were rated F3, and the most recent recorded tornado was on 2024-05-26[4].

Federal disaster declarations for natural hazards that include St. Clair County, since 1968
Incident type Declarations
Flood[2] 8
Severe Storm[2] 5
Tornado[2] 2
Hurricane[2] 1
Severe Ice Storm[2] 1
Most recent declarations
Declaration Incident Declared
DR-4819-IL[28] Severe Storms, Tornadoes, Straight-Line Winds, And Floodng 2024-09-20
DR-4676-IL[28] Severe Storm And Flooding 2022-10-14
DR-4461-IL[28] Severe Storms And Flooding 2019-09-19
DR-1771-IL[28] Severe Storms And Flooding 2008-06-24
DR-1681-IL[28] Severe Winter Storm 2007-02-09

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

Earthquakes

Before

  • Practice Drop, Cover, and Hold On with your family and coworkers.
  • Sign up for earthquake alerts that can warn you before shaking starts.
  • Make a plan with an out-of-state contact and a place to meet if you get separated.
  • Anchor heavy items such as bookcases, refrigerators and water heaters, and keep heavy things on low shelves.
  • Consider earthquake insurance. Standard homeowners policies do not cover earthquake damage.

During

  • Drop to your hands and knees, cover your head and neck, and hold on until the shaking stops.
  • Indoors, stay where you are and avoid doorways. Outdoors, move to an open area away from buildings and power lines.
  • If you are driving, pull over, stop and set the parking brake.

Source: Ready.gov, earthquakes

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

Questions people ask

Is St. Clair County at risk of flooding?
FEMA rates inland flooding risk as Relatively High compared with other US counties, with a score of 94.4 out of 100[16]. FEMA lists $71.7 million a year in expected annual loss from inland flooding[16].
Does St. Clair County have tornadoes?
NOAA's tornado database records 54 tornadoes that touched the county from 1950 to 2024[4]. FEMA rates tornado risk Relatively High compared with other US counties[15].
Is St. Clair County at risk of earthquakes?
FEMA rates earthquake risk as Relatively Moderate, with a score of 98.0 out of 100[12]. FEMA lists $50.8 million a year in expected annual loss from earthquakes[12].
Is St. Clair County at risk of hurricanes or wildfire?
FEMA rates hurricane risk as Very Low[23]. FEMA also rates wildfire risk as Very Low compared with other US counties[24].
How many disasters have been declared in St. Clair County?
OpenFEMA lists 17 federal disaster declarations for natural hazards that include the county since 1968[2].

Facts and sources

  1. FEMA National Risk Index (version 1.20, December 2025): Expected Annual Loss from all 18 natural hazards in St. Clair County is $174.6 million a year (Expected Annual Loss rating Relatively Moderate, score 95.0). Of this, buildings account for $113.6 million, injuries and deaths (converted to dollars by FEMA) for... FEMA National Risk Index
  2. OpenFEMA Disaster Declarations Summaries list 17 federal disaster declarations for natural hazards that include St. Clair County since 1968 (16 major disaster, 1 emergency or fire management). By incident type: flood 8, severe storm 5, tornado 2, hurricane 1, severe ice storm 1. Biological (such as COVID-19) and... OpenFEMA Disaster Declarations
  3. HazardFacts tally of OpenFEMA NFIP Redacted Claims (losses from 1978 to 2026): 1,469 National Flood Insurance Program claims were filed for losses in St. Clair County, 1,011 of them with a payment, and NFIP paid $7.8 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): 54 recorded tornadoes touched St. Clair County. The strongest were rated F3 (most recent of them on 1988-11-15). 3 were rated F3/EF3 or stronger. The most recent recorded tornado was on 2024-05-26. 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. Clair County is Relatively High, with a Risk Index score of 94.9 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 St. Clair County are heat wave (98.1, Relatively High), earthquake (98.0, Relatively Moderate), hail (97.5, Relatively High). HazardFacts sorted FEMA's published 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. HazardFacts sorted FEMA's hazard-type Expected Annual Loss values for St. Clair County (National Risk Index v1.20): the largest are inland flooding ($71.7 million a year), earthquake ($50.8 million a year), heat wave ($15.1 million a year), out of $174.6 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. Clair County is Relatively Low (score 37.8). 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. Clair County is Relatively High (score 74.9). 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. Clair County: Risk Index rating Relatively High (score 98.1 of 100). Expected Annual Loss $15.1 million a year (rating Relatively High). Annualized frequency 14.79 event-days per year, from recorded occurrences over a period of record of 18... FEMA National Risk Index
  12. FEMA National Risk Index (version 1.20, December 2025), earthquake in St. Clair County: Risk Index rating Relatively Moderate (score 98.0 of 100). Expected Annual Loss $50.8 million a year (rating Relatively High). FEMA's modeled annual frequency is 0.0063 events per year. FEMA National Risk Index
  13. FEMA National Risk Index (version 1.20, December 2025), hail in St. Clair County: Risk Index rating Relatively High (score 97.5 of 100). Expected Annual Loss $5.1 million a year (rating Relatively High). Annualized frequency 5.2 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), cold wave in St. Clair County: Risk Index rating Relatively High (score 96.4 of 100). Expected Annual Loss $14.8 million a year (rating Relatively High). Annualized frequency 1.42 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), tornado in St. Clair County: Risk Index rating Relatively High (score 95.4 of 100). Expected Annual Loss $13.0 million a year (rating Relatively High). Annualized frequency 0.58 events per year, from recorded occurrences over a period of record of 38 years. FEMA National Risk Index
  16. FEMA National Risk Index (version 1.20, December 2025), inland flooding in St. Clair County: Risk Index rating Relatively High (score 94.4 of 100). Expected Annual Loss $71.7 million a year (rating Relatively High). Annualized frequency 1.79 event-days per year, from recorded occurrences over a period of record of... FEMA National Risk Index
  17. FEMA National Risk Index (version 1.20, December 2025), lightning in St. Clair County: Risk Index rating Relatively High (score 93.7 of 100). Expected Annual Loss $1.6 million a year (rating Relatively High). Annualized frequency 51.93 events per year, from recorded occurrences over a period of record of 24 years. FEMA National Risk Index
  18. FEMA National Risk Index (version 1.20, December 2025), ice storm in St. Clair County: Risk Index rating Relatively High (score 91.0 of 100). Expected Annual Loss $1.0 million a year (rating Relatively High). Annualized frequency 1.39 event-days per year, from recorded occurrences over a period of record of 68 years. FEMA National Risk Index
  19. FEMA National Risk Index (version 1.20, December 2025), winter weather in St. Clair County: Risk Index rating Relatively High (score 87.2 of 100). Expected Annual Loss $333,000 a year (rating Relatively High). Annualized frequency 9 events per year, from recorded occurrences over a period of record of 18 years. FEMA National Risk Index
  20. FEMA National Risk Index (version 1.20, December 2025), landslide in St. Clair County: Risk Index rating Relatively Low (score 84.2 of 100). Expected Annual Loss $28,000 a year (rating Relatively Low). FEMA National Risk Index
  21. FEMA National Risk Index (version 1.20, December 2025), drought in St. Clair County: Risk Index rating Relatively Low (score 61.4 of 100). Expected Annual Loss $314,000 a year (rating Relatively Low). Annualized frequency 1.66 event-days per year, from recorded occurrences over a period of record of 22 years. FEMA National Risk Index
  22. FEMA National Risk Index (version 1.20, December 2025), strong wind in St. Clair County: Risk Index rating Relatively Moderate (score 53.9 of 100). Expected Annual Loss $627,000 a year (rating Relatively Moderate). Annualized frequency 6.15 events per year, from recorded occurrences over a period of record of 38... FEMA National Risk Index
  23. FEMA National Risk Index (version 1.20, December 2025), hurricane in St. Clair County: Risk Index rating Very Low (score 34.8 of 100). Expected Annual Loss $21,000 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), wildfire in St. Clair County: Risk Index rating Very Low (score 15.0 of 100). Expected Annual Loss $5,162 a year (rating Very Low). FEMA's modeled annual frequency is 0 events per year. FEMA National Risk Index
  25. FEMA National Risk Index (version 1.20, December 2025) rates these hazards Not Applicable for St. Clair 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): 1,007 residential flood insurance contracts were in force in St. Clair County, out of 101,953 residential structures, a penetration rate of 1%. 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.