Hazard Plain Automated baseline

Johnson County, IL

Risk-assessment baseline packet

County FIPS:
17087
Release:
2026-10
Data as of:
2026-09-30
Storm Events data through:
2026-06-30

Hazard Plain is an independent product built from public federal data. It is not a FEMA document and is not reviewed or endorsed by FEMA or any state agency.

Hazard Plain release 2026-10, as of 2026-09-30.

Summary

Plan status as of 2026-09-30: Expired on 2025-12-03. Plan: Johnson County 2020 Hazard Mitigation Plan (FEMA plan 105793), approved 2020-12-04.

Since the plan was approved on 2020-12-04: no new hazard declaration and 104 NOAA Storm Events records; details under "What changed since your last plan".

Highest expected annual loss (FEMA National Risk Index, modeled total; see B1-a): Earthquake ($4,353,194 a year), Inland Flooding ($3,197,863) and Cold Wave ($1,193,321).

The tables that follow are organized by the items of FEMA's Local Mitigation Plan Review Tool, Element B (B1-a to B2-c); each heading says which item its tables support.

Plan clock

Status:
Expired on 2025-12-03
Plan:
Johnson County 2020 Hazard Mitigation Plan (FEMA plan 105793)
Approved:
2020-12-04
Days since expiry:
301
Update underway:
none recorded in FEMA's plan tracker

Until a new plan is approved, FEMA mitigation project grants (HMGP, FMA) need a FEMA exception (44 CFR 201.6(a)(3)).

What changed since your last plan (approved 2020-12-04)

New federal declarations:
none
Storm Events records since approval:
104 records (data through 2026-06-30)
Repetitive loss now:
FMA RL 0, SRL 0 (44 CFR 77.2); any definition: 0
Repeat-flood change:
this release sets the baseline count.

Sources: 1, 2, 4, 6 (numbered list at the end)

Plan status for every jurisdiction listed in this county

Source: 1

JurisdictionTypeStatusPlanApprovedExpiresDays to expirynegative = days since expiry
Johnson CountyCountyExpired on 2025-12-03Johnson County 2020 Hazard Mitigation Plan (FEMA plan 105793)2020-12-042025-12-03-301
Belknap villageVillageExpired on 2025-12-03Johnson County 2020 Hazard Mitigation Plan (FEMA plan 105793)2020-12-042025-12-03-301
Buncombe villageVillageExpired on 2025-12-03Johnson County 2020 Hazard Mitigation Plan (FEMA plan 105793)2020-12-042025-12-03-301
Cypress villageVillageExpired on 2025-12-03Johnson County 2020 Hazard Mitigation Plan (FEMA plan 105793)2020-12-042025-12-03-301
Goreville villageVillageExpired on 2025-12-03Johnson County 2020 Hazard Mitigation Plan (FEMA plan 105793)2020-12-042025-12-03-301
New Burnside villageVillageExpired on 2025-12-03Johnson County 2020 Hazard Mitigation Plan (FEMA plan 105793)2020-12-042025-12-03-301
Simpson villageVillageExpired on 2025-12-03Johnson County 2020 Hazard Mitigation Plan (FEMA plan 105793)2020-12-042025-12-03-301
Vienna cityCityExpired on 2025-12-03Johnson County 2020 Hazard Mitigation Plan (FEMA plan 105793)2020-12-042025-12-03-301

State plan status and tribal plans in this state: see the state page.

Supports FEMA checklist item B1-a: hazard identification

Hazards NRI does not cover (local data needed)

  • dam failure (incl. upstream dams)
  • levee failure
  • flash flood as its own subtype
  • ice jams
  • debris flows
  • erosion (riverine and coastal)
  • land subsidence and sinkholes
  • expansive soils

The 18 National Risk Index hazards, ranked by expected annual loss (EAL)

Sources: 5, 6

Rank by EALHazardNRI risk ratingEAL ratingEAL buildingsmodeled dollars per yearEAL agriculturemodeled dollars per yearCost of expected deaths and injuriesFEMA's dollar value per year, not property damageEAL total (see note)modeled dollars per yearStorm Events records, 1996 to 2026-06-30countStorm Events coverage note
1EarthquakeRelatively ModerateRelatively Moderate$2,638,807n/a$1,714,386$4,353,194Storm Events does not record earthquakes.
2Inland FloodingRelatively LowVery Low$3,179,437$503$17,923$3,197,86326
3Cold WaveRelatively LowRelatively Moderate$42$188,629$1,004,650$1,193,32176Includes 53 Frost/Freeze records (outside NRI's Cold Wave definition; counted in this table and in B1-d, not in the B1-e descriptor).
4TornadoRelatively LowRelatively Low$423,472$773$665,954$1,090,19915
5Strong WindRelatively ModerateRelatively Moderate$329,842$40,944$305,279$676,066144Includes 6 High Wind and 58 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
6Heat WaveRelatively LowRelatively Low$46$1$623,302$623,34886
7HailRelatively LowRelatively Low$341,576$319$4,411$346,30676
8Ice StormRelatively ModerateRelatively Moderate$129,848n/a$15,432$145,2805
9DroughtRelatively LowRelatively Lown/a$124,558n/a$124,55832
10LightningRelatively LowRelatively Low$4,214n/a$86,812$91,0260No recorded events in Storm Events since 1996 (data through 2026-06-30).
11Winter WeatherRelatively ModerateRelatively Moderate$63,765$58$12,355$76,178108
12HurricaneVery LowVery Low$16,725$2,367$95$19,1860No recorded events in Storm Events since 1996 (data through 2026-06-30).
13WildfireVery LowVery Low$1,912$6$715$2,6330No recorded events in Storm Events since 1996 (data through 2026-06-30).
14LandslideVery LowVery Low$75n/a$561$6360No recorded events in Storm Events since 1996 (data through 2026-06-30).

Total = buildings + agriculture + population equivalence; FEMA values each expected death (or 10 injuries) at $13.7 million (2024 dollars).

NRI risk rating combines expected annual loss with social vulnerability and community resilience; EAL rating rates expected annual loss alone. Both compare this county with all U.S. counties.

Local data needed: state and local lightning, wildfire and landslide records (Storm Events records these hazards only in part).

Not applicable to this county per NRI, with no federal declaration and no Storm Events record since 1996: avalanche, coastal flooding, tsunami and volcanic activity. That is the evidence for leaving them out of the plan.

The state hazard mitigation plan also lists hazards for this county; FEMA asks the plan to explain any hazard it leaves out.

Supports FEMA checklist item B1-b: hazard location

Affects the whole county (national data give no location within it): Cold Wave, Drought, Hail, Heat Wave, Ice Storm, Lightning, Strong Wind and Winter Weather.

Inland Flooding: The FEMA Flood Insurance Rate Map (FIRM) is the required location source for flooding. See the FEMA Flood Map Service Center (https://msc.fema.gov) for this county.

Hazards that vary within the county: highest-rated census tracts

Source: 5

HazardHighest-rated census tractsNRI risk rating, score 0 to 100
Earthquaketract 9778 (Relatively High, 97.0); tract 9776 (Relatively High, 96.2); tract 9777 (Relatively High, 91.6)
Hurricanetract 9776 (Relatively Low, 53.1); tract 9778 (Very Low, 50.9); tract 9777 (Very Low, 47.8)
Landslidetract 9776 (Relatively Low, 90.5); tract 9778 (Relatively Low, 82.2); tract 9777 (Relatively Low, 81.9)
Tornadotract 9776 (Very High, 96.2); tract 9778 (Relatively High, 92.0); tract 9777 (Relatively High, 84.7)
Wildfiretract 9776 (Relatively Low, 72.1); tract 9777 (Very Low, 67.5); tract 9778 (Very Low, 61.6)

Up to 3 census tracts per hazard, highest National Risk Index rating first, then highest score; a tract number is the Census tract number (for example 9778 is Census Tract 9778). FEMA's Resilience Analysis and Planning Tool maps the National Risk Index for every tract: https://www.fema.gov/emergency-managers/practitioners/resilience-analysis-and-planning-tool

Supports FEMA checklist item B1-c: hazard extent

Extent: scale, observed range and worst recorded event per hazard

Sources: 6, 7

HazardScaleRecordscount and yearsObserved rangeWorst recorded eventMost damaging (when different)How it applies to jurisdictionsNote
Cold/Wind Chill, Extreme Cold/Wind Chillwind chill23 records, 1996 to 2026 (23 zone-level)1 day to 24 days (median 1 day); 22 with a recorded value2000-12-12 to 2001-01-04 (2 records, 1 of them a monthly summary record), zone-levelCountywide (zone-level records).
Frost/Freeze (outside NRI's Cold Wave definition)crop damage53 records, 1997 to 2024 (53 zone-level)Frost/Freeze, 2007-04-08, $3,000,000 crop damage (2007 dollars); NWS zone ILZ089Countywide (zone-level records).
DroughtU.S. Drought Monitor scale (D0 to D4)32 records, 1996 to 2025 (32 zone-level)15 days to 246 days (median 34 days); 13 with a recorded value246 days (about 8.1 months), 2012-05-12 to 2013-01-12, a run of 9 consecutive Storm Events drought records, zone-levelDrought, 2007-09-01, $0 property; $3,450,000 crops (zone total, 2007 dollars)Countywide (zone-level records).Storm Events enters a drought at D2 or worse east of the Rockies and D3 or worse from the Rockies west (NWS Instruction 10-1605); NRI drought counts D3 and D4 only.
EarthquakeModified Mercalli (local data)0Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hailhail size (inches)88 records, 1965 to 20260.75 in to 3 in (median 1 in); 88 with a recorded value3 in hail, 1975-07-05; same size also recorded on 1965-11-26Hail, 2000-05-23, $7,000,000 property; crops not reported (2000 dollars)Event records naming jurisdictions in the plan: Vienna city (21 records), Goreville village (14 records), Cypress village (10 records), New Burnside village (6 records), Belknap village (4 records), Buncombe village (4 records), Simpson village (4 records).
Excessive Heat, Heatheat index (in event narratives)86 records, 1997 to 2025 (86 zone-level)1 day to 14 days (median 2 days); 72 with a recorded value14 consecutive days, 1999-07-18 to 1999-07-31, zone-levelCountywide (zone-level records).Heat records from November to March (unseasonable warmth, not a heat wave) are counted but not used for the longest run.
Hurricane, Tropical Storm, Tropical DepressionSaffir-Simpson0Storm Events files every zone of a storm's episode under the storm's type; flooding from the storm is filed as Flood or Flash Flood records.
Ice StormSperry-Piltz ice scale (local data)5 records, 1997 to 2025 (5 zone-level)Ice Storm, 2025-01-05, $25,000 property; $0 crops (2025 dollars); NWS zone ILZ089Countywide (zone-level records).
Flash Flood, Flood, Lakeshore Flooddamage and flood days (flood depth: FIRM)26 records, 1996 to 2024 (2 zone-level)Flood, 2008-03-18, $1,600,000 property; $0 crops (2008 dollars)Event records naming jurisdictions in the plan: Vienna city (8 records), Buncombe village (3 records), Belknap village (2 records), Cypress village (1 record), Goreville village (1 record), New Burnside village (1 record), Simpson village (1 record). Zone-level records (2) apply countywide.Flood depth: see the FEMA Flood Insurance Rate Map. Storm Events damage is often $0 or blank for floods, major ones included; FEMA Public Assistance by declaration (B1-d) shows which floods cost the most.
Debris Flownone (count and damage only)0
Lightningannualized frequency (the measure FEMA's Local Mitigation Planning Handbook names)0Storm Events lists lightning with damage or casualties.
High Wind and Strong Wind (outside NRI's Strong Wind definition)wind speed (kt and mph)64 records, 1996 to 2025 (64 zone-level)28 kt (32 mph) to 52 kt (60 mph) (median 39 kt (45 mph)); 60 with a recorded value52 kt (60 mph) estimated gust, High Wind, 2008-09-14; NWS zone ILZ089Countywide (zone-level records).
Thunderstorm Windwind speed (kt and mph)96 records, 1974 to 202550 kt (58 mph) to 83 kt (96 mph) (median 52 kt (60 mph)); 80 with a recorded value83 kt (96 mph) measured gust, Thunderstorm Wind, 2011-04-19Thunderstorm Wind, 2008-01-29, $150,000 property; $0 crops (2008 dollars)Event records naming jurisdictions in the plan: Vienna city (32 records), Cypress village (12 records), Goreville village (11 records), Buncombe village (8 records), Belknap village (6 records), Simpson village (6 records), New Burnside village (5 records).
TornadoEnhanced Fujita (Fujita before Feb 2007)21 records, 1957 to 2025F/EF0 to F/EF3 (median F/EF1); 21 with a recorded valueEF3 tornado, 2024-05-26, 4.87 mi within this county, 300 yd wide, $750,000 property; $0 crops (2024 dollars), 1 direct injuryTornado, 2002-04-28, $3,000,000 property; crops not reported (2002 dollars)Event records naming jurisdictions in the plan: Goreville village (4 records), Cypress village (3 records), Belknap village (1 record), Buncombe village (1 record), Vienna city (1 record).Before 1996 a tornado is listed once, under the county where it began, with its whole path's rating and length; from 1996 on, each county lists its own segment. Length is not used to rank tornadoes (see Methods).
Wildfireacres burned (local data)0
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleetnone in data (snowfall: local data)108 records, 1996 to 2026 (108 zone-level)Winter Storm, 2008-02-11, $1,000,000 property; $0 crops (2008 dollars); NWS zone ILZ089Countywide (zone-level records).

In event narratives only (local data needed): wind chill, temperature, heat index, ice thickness, acres burned and snow depth; any physical measure of debris flow and lightning.

Storm Events records are more complete after 1996; before 1996 only Tornado (from 1950), Hail and Thunderstorm Wind (from 1955) exist. Zone-level records from zones that no NWS zone-county file places in this county (mostly before 2020) are not counted here (the Methods page explains the zone matching).

Dollars are nominal (as reported), labeled with the year; not adjusted for inflation.

A monthly summary record covers most or all of a month; it does not count days at wave conditions.

Supports FEMA checklist item B1-d: previous occurrences

Federal declarations for this county: 7 declarations covering 4 separate hazard incidents counted in this packet (declarations for the same incident count once; non-natural and evacuation-only declarations are not counted).

Federal disaster declarations for this county

Sources: 1, 2, 3

DeclaredIncident beganFEMA numberTypeTitleMapped hazardCounty Public Assistancefederal share obligated, nominal dollarsFlagsNotes
2020-03-262020-01-20DR-4489-ILMajor disasterCOVID-19 PandemicNon-natural, not countednone placed in this county by FEMA's record; $797,909.42 for this declaration is not placed in any county (see the state page)in the 12 months before plan approval
2020-03-132020-01-20EM-3435-ILEmergencyCOVID-19Non-natural, not countedno Public Assistance recordedin the 12 months before plan approvalsame incident as DR-4489
2009-03-022009-01-26DR-1826-ILMajor disasterSevere Winter StormWinter Weather$184,688.85
2005-09-072005-08-29EM-3230-ILEmergencyHurricane Katrina EvacuationHurricane: evacuation support, not a local hazard event; not countedno Public Assistance recorded
2005-02-012004-12-21EM-3199-ILEmergencyRecord/Near Record SnowWinter Weather$26,666.28
2002-05-212002-04-21DR-1416-ILMajor disasterSevere Storms, Tornadoes and FloodingTornado (primary); also designated: Inland Flooding$3,608,833.08
1973-04-261973-04-26DR-373-ILMajor disasterSevere Storms & FloodingInland Floodingno Public Assistance recorded

County Public Assistance: applicants the FEMA record places in this county, including any state agencies FEMA files there; statewide rows are listed on the state page; federal share obligated, nominal dollars.

Statewide declarations

Source: 2

DeclaredIncident beganFEMA numberTypeTitleMapped hazard
1961-05-271961-05-27DR-115-ILMajor disasterFloods & TornadoesInland Flooding (primary); also designated: Tornado
1957-06-221957-06-22DR-78-ILMajor disasterFloodsInland Flooding

FEMA recorded these with designated area Statewide and no county, so they are listed on every county page in the state and not counted with county rows. Local data needed: whether each one affected this county.

Public Assistance not placed in any Illinois county: 1 row, $797,909.42; listed on the Illinois state page.

Source: 3

Previous occurrences by hazard, with explicit no-event rows

Sources: 2, 6, 7

HazardStorm Events records, all years on file(years in the Period column)Since plan approvalrecordsIn the 12 months before plan approvalrecordsLast 5 yearsrecordsDeclared incidents, all yearsseparate disastersDeclared since approvalseparate disastersPeriodStatement
Cold Wave7618414001996 to 2026-06-30Includes 53 Frost/Freeze records.
Drought32505001996 to 2026-06-30
Earthquake000000Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail88605001955 to 2026-06-30
Heat Wave8626223001996 to 2026-06-30
Hurricane0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Ice Storm5101001996 to 2026-06-30
Inland Flooding26212201996 to 2026-06-30
Landslide0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Lightning0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Strong Wind16022320001955 to 2026-06-30Includes 6 High Wind and 58 Strong Wind records.
Tornado21303101950 to 2026-06-30
Wildfire0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Winter Weather10821017201996 to 2026-06-30

Notable Storm Events records

Sources: 1, 6, 7

DateEvent typeMagnitude or extentDamagenominal dollarsDeaths, injuriesdirect onlyLocationFlagsWhy listed
2025-01-05Ice Storm$25,000 property; $0 crops (zone total, 2025 dollars)0, 0NWS zone ILZ089 (JOHNSON), zone-levelnew since last plan; within last 5 yearsB1-c worst recorded: Ice Storm
2024-05-26TornadoEF3, 4.87 mi within this county, 300 yd wide$750,000 property; $0 crops (2024 dollars)0, 1GOREVILLEnew since last plan; within last 5 yearsB1-c worst recorded: Tornado
2016-07-07Flood$15,000 property; $0 crops (2016 dollars)1, 1VIENNAdeaths or injuries recorded
2012-07-01Thunderstorm Wind52 kt (60 mph) estimated gust$10,000 property; $0 crops (2012 dollars)0, 4GOREVILLEdeaths or injuries recorded
2011-04-19Thunderstorm Wind83 kt (96 mph) measured gust$40,000 property; $0 crops (2011 dollars)0, 0BUNCOMBEB1-c worst recorded: Thunderstorm Wind
2008-09-14High Wind52 kt (60 mph) estimated gust$1,000,000 property; $500,000 crops (zone total, 2008 dollars)0, 0NWS zone ILZ089 (JOHNSON), zone-levelB1-c worst recorded: High Wind and Strong Wind
2008-03-18Flood$1,600,000 property; $0 crops (2008 dollars)0, 0GOREVILLE to WHITE HILLB1-c worst recorded: Flash Flood, Flood, Lakeshore Flood
2007-04-08Frost/Freeze$0 property; $3,000,000 crops (zone total, 2007 dollars)0, 0NWS zone ILZ089 (JOHNSON), zone-levelB1-c worst recorded: Frost/Freeze
2000-12-12Extreme Cold/Wind Chilldamage not reported0, 0NWS zone ILZ089 (JOHNSON), zone-levelB1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill
1999-07-18Heatdamage not reported0, 0NWS zone ILZ089 (JOHNSON), zone-levelB1-c worst recorded: Excessive Heat, Heat
1975-07-05Hail3 indamage not recorded (pre-1996 record)0, 0location not recordedB1-c worst recorded: Hail
1972-04-14TornadoF2, 4.9 mi path length (whole path, pre-1996), 30 yd wide$25,000 property; crops not recorded (1972 dollars)0, 5location not recordeddeaths or injuries recorded

The full list is in the Excel file, sheet "B1-d Storm Events history" (602 rows).

Location is the place NOAA recorded, as written in its data; it need not be a jurisdiction in this plan.

Local data needed: state-declared emergencies, from your state emergency management agency (federal data do not include them).

FEMA's declaration data list no tribal or special-area declarations for this state.

Supports FEMA checklist item B1-e: probability of future events

Probability: FEMA annualized frequency and descriptor per hazard

Sources: 5, 6

HazardFEMA annualized frequency (modeled)unit per rowUnitIn plain termsDescriptorDescriptor basisNRI events or days in its record period (hail, wind and tornado are area-weighted, so can be fractional)NRI periodLocationNote
Cold Wave1.11event-days per yearabout 1.11 days per yearLikelyStorm Events event-days in 15 of 30 years, 1996 to 2025 (50%)212005-11-12 to 2024-11-12 (19 years)countywide
Drought4.02event-days per yearabout 4.02 days per yearLikelyStorm Events event-days in 12 of 30 years, 1996 to 2025 (40%)1472000 to 2025 (25.25 years; D3 and D4 only)countywide
Earthquake0.01annual probability at a locationchance a given location in the county has at least minor-damage shaking in a year: 1%not shownmodeledsee B1-fNo descriptor (Storm Events does not record earthquakes).
Hail3.2events per yearabout 3.2 per yearHighly likelyFEMA annualized frequency (modeled)121.7 (modeled)1986 to 2023 (38 years)countywide
Heat Wave10.5event-days per yearabout 10.5 days per yearLikelyStorm Events event-days in 25 of 30 years, 1996 to 2025 (83.3%)1452005-11-12 to 2024-11-12 (19 years)countywide
Hurricane0.0217events per yearabout 1 in 46 yearsPossibleFEMA annualized frequency (modeled)61851 to 2024 (Atlantic)see B1-fNRI counts hurricane and tropical storm tracks passing within storm-force wind range; federal declarations are in B1-d.
Ice Storm0.912event-days per yearabout 0.912 days per yearLikelyStorm Events event-days in 4 of 30 years, 1996 to 2025 (13.3%)621946-12-31 to 2014-02-12 (67 years)countywide
Inland Flooding0.821event-days per yearabout 0.821 days per yearLikelyStorm Events event-days in 17 of 30 years, 1996 to 2025 (56.7%)231996 to 2023 (28 years)see B1-f
Landslide0.819events per year (modeled)about 0.82 per yearLikelyFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Lightning55.1days per year with a strikeabout 55.1 days per yearHighly likelyFEMA annualized frequency (modeled)not shown1995 to 2023 (29 years; CONUS)countywide
Strong Wind4.04events per yearabout 4.04 per yearHighly likelyFEMA annualized frequency (modeled)1541986 to 2023 (38 years)countywide
Tornado0.299events per yearabout 1 in 3 yearsLikelyFEMA annualized frequency (modeled)not shown1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)see B1-f
Wildfire0.000361annual probability at a locationchance a given location in the county burns in a year: 0.0361%Storm Events records in 0 of 30 years, 1996 to 2025 (0%)not shownmodeledsee B1-fNo descriptor: no Storm Events record 1996 to 2025
Winter Weather7.47event-days per yearabout 7.47 days per yearHighly likelyStorm Events event-days in 29 of 30 years, 1996 to 2025 (96.7%)1422005-11-12 to 2024-11-12 (19 years)countywide

FEMA annualized frequency (modeled) is the National Risk Index v1.20 (December 2025) estimate of how often a hazard affects this county in a year; it is not recorded events divided by years, and its unit differs by hazard (events, event-days, or days with a lightning strike per year). For earthquake, wildfire, coastal flooding and tsunami the value is the chance (or number of events) at a location in the county, not across the county, so no "1 in N years" is given and the descriptor comes from Storm Events where it has a record (none for earthquake). The Methods page gives each hazard's method, from FEMA's National Risk Index Technical Documentation v1.20.

Where NRI gives event-days, the descriptor comes from the share of years with a Storm Events record; NRI's source records more events, so the two differ.

Descriptor scale used in this packet (defined per unit)

Sources: 5, 6

UnitDescriptorDefinition
events per yearHighly likely1 or more per year
events per yearLikelyabout once in 1 to 10 years
events per yearPossibleabout once in 10 to 100 years
events per yearUnlikelyless than once in 100 years
annual probabilityLikely10% to under 100% chance in a given year
annual probabilityPossible1% to under 10% chance in a given year
annual probabilityUnlikelyunder 1% chance in a given year
event-days (share of years)Highly likelyevent-days recorded in 90% or more of years
event-days (share of years)Likelyevent-days recorded in 10% to under 90% of years
event-days (share of years)Possibleevent-days recorded in some years but under 10% of years
lightning strike-daysHighly likelycloud-to-ground strikes on 1 or more days per year

Intensity bands: historical frequency (Storm Events)

Source: 6

HazardBandYearsEventscounty-coded recordsYears in periodEvents per yearevents / years
Hail1.00-1.99 in1996 to 202541301.37
Hail2.00 in+1996 to 20254300.133
Thunderstorm Wind (counted as NRI Strong Wind)50-64 kt1996 to 202565302.17
Thunderstorm Wind (counted as NRI Strong Wind)65 kt+1996 to 20259300.3
Thunderstorm Wind (counted as NRI Strong Wind)unmeasured or below 50 kt1996 to 20256300.2
TornadoEF0-11996 to 202510300.333
TornadoEF2-31996 to 20255300.167
TornadoEF4-51996 to 20250300
Tornadounrated (EFU)1996 to 20250300

The bands show how often events of each severity were recorded in this county, to profile how severe events have been (FEMA's probability item asks for the range of intensities).

Hail smaller than 1 inch is not counted: on 2010-01-05 the National Weather Service raised its severe-hail threshold from 3/4 inch to 1 inch, so smaller reports became less common after 2009 (NWS Service Change Notice 09-52). NRI hail frequency uses a 0.75 inch threshold.

Optional: future conditions. Not a required item in the 2025 FEMA Local Mitigation Planning Policy Guide; some states ask for it. The federal Climate Mapping for Resilience and Adaptation (CMRA) site gives county exposure to future climate conditions (https://resilience.climate.gov/).

Supports FEMA checklist item B1-f: hazards that vary across jurisdictions

Range of census tract risk within the county

Source: 5

HazardTractsrated of allNRI risk score, 0 to 100Tracts by rating
MinMedianMax
Cold Wave4 of 483.192.895.9Very High 1, Relatively High 3
Drought4 of 478.892.195.8Relatively Moderate 2, Relatively Low 1, Very Low 1
Earthquake4 of 477.593.997.0Relatively High 3, Relatively Low 1
Hail4 of 454.692.296.4Relatively High 3, Relatively Low 1
Heat Wave4 of 483.890.794.3Relatively High 3, Relatively Moderate 1
Hurricane4 of 428.849.453.1Relatively Low 1, Very Low 3
Ice Storm4 of 456.093.496.3Relatively High 3, Relatively Low 1
Inland Flooding4 of 40.772.495.2Relatively High 2, Relatively Moderate 1, Very Low 1
Landslide4 of 419.382.190.5Relatively Low 3, Very Low 1
Lightning4 of 463.578.788.1Relatively High 2, Relatively Moderate 2
Strong Wind4 of 485.397.699.2Very High 3, Relatively High 1
Tornado4 of 466.588.396.2Very High 1, Relatively High 2, Relatively Moderate 1
Wildfire4 of 423.364.672.1Relatively Low 1, Very Low 3
Winter Weather4 of 460.494.797.9Very High 2, Relatively High 1, Relatively Moderate 1

Drought: Agriculture is all of NRI's expected annual loss for this hazard in the county, so the tract range mostly reflects where crop and livestock value is.

Rated tracts only: No Rating (score 0.0), Not Applicable and Insufficient Data tracts are counted but not used for the minimum, median and maximum.

The score ranks a tract against all U.S. tracts (100 = highest). The rating is FEMA's category for the tract's risk value, computed differently, so the two can disagree.

Frequency data for cold wave, drought, hail, heat wave, ice storm, lightning, strong wind and winter weather are county-wide or coarse (49 km grid or NWS zone), the same for every jurisdiction; the tract range mostly reflects where buildings and people are (crop and livestock value where a line above names agriculture).

Each jurisdiction (starting figures from federal data)

Sources: 1, 3, 4, 6

JurisdictionTypePlan statusRepetitive lossFMA RL and SRL (44 CFR 77.2); repeat-flood, any definitionPublic Assistance to this jurisdictionFEMA records matched by applicant name; federal share obligated, nominal dollarsEvent records naming this placeall years; since its plan
Johnson CountyCountyExpired on 2025-12-03FMA RL 0, SRL 0; any 0$142,478.730 total; 0 since its plan
Belknap villageVillageExpired on 2025-12-03FMA RL 0, SRL 0; any 0$2,423.9313 total; 1 since its plan
Buncombe villageVillageExpired on 2025-12-03FMA RL 0, SRL 0; any 0$5,888.8716 total; 4 since its plan
Cypress villageVillageExpired on 2025-12-03FMA RL 0, SRL 0; any 0$26,797.6126 total; 2 since its plan
Goreville villageVillageExpired on 2025-12-03FMA RL 0, SRL 0; any 0$3,988.1430 total; 3 since its plan
New Burnside villageVillageExpired on 2025-12-03FMA RL 0, SRL 0; any 0no Public Assistance recorded12 total; 1 since its plan
Simpson villageVillageExpired on 2025-12-03FMA RL 0, SRL 0; any 0no Public Assistance recorded11 total; 1 since its plan
Vienna cityCityExpired on 2025-12-03FMA RL 0, SRL 0; any 0$24,811.3962 total; 6 since its plan

Repetitive-loss counts are for whole NFIP communities, which can extend beyond this county (see the note in B2-c).

County Public Assistance in B1-d also includes applicants filed under the county that are not jurisdictions in this plan (for example state agencies, special districts and nonprofits), so the jurisdiction rows add up to less.

Supports FEMA checklist items B2-a and B2-b: vulnerability and potential impacts

Local data needed

The table below gives county-level starting figures; the plan describes impacts for each jurisdiction and its own assets.

  • Critical facilities and lifelines per hazard
  • A problem statement per jurisdiction per hazard
  • Changes in development in hazard-prone areas since the last approval, or a statement of none (E1-a)
  • Future assets

County-level starter: exposure, expected annual loss and damage since the plan

Sources: 1, 2, 3, 5, 6, 7

HazardBuilding exposuremodeled dollarsAgriculture exposuremodeled dollarsPopulation exposedpeopleEAL buildingsmodeled dollars per yearEAL agriculturemodeled dollars per yearCost of expected deaths and injuriesFEMA's dollar value per year, not property damageEAL as % of exposurebuildings; agriculture where notedStorm Events damage since 2020-12-04county-coded records, property plus crops, nominal dollarsZone-level damage since planproperty plus crops, reported for the zonePublic Assistance since plannominal dollars; see noteNote
Cold Wave$3,575,931,492$23,391,06513,301$42$188,629$1,004,650under 0.0001%$0
Droughtn/a$16,739,618n/an/a$124,558n/a0.744% (agriculture)$0NRI has no building exposure for this hazard; agriculture shown
Earthquake$5,957,208,830n/a13,308$2,638,807n/a$1,714,3860.0443%
Hail$3,575,931,492$23,391,06513,301$341,576$319$4,4110.00955%$0
Heat Wave$3,575,931,492$23,391,06513,301$46$1$623,302under 0.0001%$0
Hurricane$3,575,931,492$23,254,40113,301$16,725$2,367$950.000468%
Ice Storm$3,575,931,492n/a13,301$129,848n/a$15,4320.00363%$25,000
Inland Flooding$3,562,570,212$1,265,409101$3,179,437$503$17,923n/a (see note)$0NRI counts the full building value of any census block with some flood loss; this is not the value of buildings in the floodplain. Use local FIRM overlays for B2-a/B2-b.
Landslide$139,926,977n/a442$75n/a$561under 0.0001%
Lightning$3,575,931,492n/a13,301$4,214n/a$86,8120.000118%
Strong Wind$3,575,931,492$23,391,06513,301$329,842$40,944$305,2790.00922%$142,000$12,000Storm Events damage since the plan includes 12 zone-level Strong Wind records ($12,000): a NOAA non-thunderstorm wind type, outside NRI's Strong Wind definition.
Tornado$3,575,931,492$23,391,06513,301$423,472$773$665,9540.0118%$1,765,000
Wildfire$88,956,262$2,764,6751,297$1,912$6$7150.00215%
Winter Weather$3,575,931,492$23,391,06513,301$63,765$58$12,3550.00178%$0

Totals since 2020-12-04 (Storm Events through 2026-06-30): 21 county-coded records, 21 with a damage value recorded (including $0), $1,907,000; 83 zone-level records, 83 with a damage value recorded (including $0), $37,000 reported for the zone; Public Assistance: no counted declaration since the plan.

FEMA does not split Public Assistance by hazard. A declaration mapped to several hazards is listed under each of them with its full amount, so the per-hazard column does not add up to the total; the unit total counts each declaration once.

NRI computes earthquake exposure on its own basis, so it exceeds the county building value in B2-a.

Supports FEMA checklist item B2-a: vulnerability (county context)

County context

Source: 5

MeasureValue
Population13,301
Building value (total, not at risk)$3,575,931,492
Agriculture value (total, not at risk)$23,391,065
NRI risk rating (all hazards)Relatively Low
Expected annual loss, buildings and agriculture, all hazards$7,487,917
Expected annual loss, population equivalence, all hazards (NRI values each statistical life at $13.7M; a modeled value of expected deaths and injuries, not property damage)$4,451,876
Social vulnerability ratingVery High
Community resilience ratingRelatively Moderate
NRI versionDecember 2025

FEMA's all-hazard expected annual loss adds buildings, agriculture and population equivalence; this table gives the property part and the population-equivalence part as separate rows.

Social vulnerability: higher means people are more likely to be harmed and slower to recover. Community resilience: lower means the community is less able to recover. High social vulnerability and low resilience both raise the NRI risk rating.

Supports FEMA checklist item B2-c: repetitive loss properties

Repetitive loss in this county, both definitions

Sources: 1, 4

DefinitionPropertiesSevere repetitive lossProperties
Repetitive loss, FMA definition (44 CFR 77.2)0Severe repetitive loss, FMA definition (44 CFR 77.2)0
Repetitive loss, NFIP insurance definition0Severe repetitive loss, NFIP insurance definition0

The state NFIP coordinator's list, the source FEMA's Handbook names, often uses the NFIP insurance definition (second row).

Repeat-flood properties: county and state-level rows

Sources: 1, 4

ScopeRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
County total0000000
Statewide, no county in FEMA's file0050500

The statewide row counts properties FEMA's file gives with no county in this state; they are listed for reference and are not in this county's counts.

Repeat-flood properties by jurisdiction in the plan (NFIP community)

Sources: 1, 4

JurisdictionNFIP community IDRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
Johnson County1708170000000
Belknap village1711780000000
Buncombe village1711790000000
Cypress village1711800000000
Goreville village1711810000000
New Burnside village1711820000000
Simpson village1711830000000
Vienna city1703190000000

Counts by occupancy group for each jurisdiction are in the Excel file, sheet "B2-c Jurisdictions".

Jurisdiction rows are whole NFIP communities and need not add up to the county total: a community that extends into another county is counted in full on each jurisdiction row, while the county table counts only its part in this county.

County repeat-flood properties by occupancy group: 0 in every occupancy group.

Sources: 1, 4

FMA RL and FMA SRL are the Flood Mitigation Assistance definitions (44 CFR 77.2), the ones the FEMA Local Mitigation Planning Policy Guide cites. NFIP repetitive loss (the FEMA insurance definition) is 2 or more claims over $1,000 in 10 years, and a property can leave that group once it is mitigated. Also shown: NFIP severe repetitive loss, any category, mitigated and currently insured. The Methods page gives the OpenFEMA field details.

Counts are aggregates of FEMA's public NFIP Multiple Loss Properties file (FEMA's data date 2026-08-02; file version 2026-08-04). No property is identified. County assignment is FEMA's geocode.

In this county 0 properties are FMA repetitive loss but not NFIP repetitive loss, and 0 properties are NFIP repetitive loss but not FMA repetitive loss.

Exact counts; no count suppression.

Sources

Tables cite these sources by number. The full list, for the plan's bibliography (FEMA review item A4-a):

  1. FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-29T134039Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
  2. FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-29T162832Z, pulled 2026-09-30, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
  3. FEMA, OpenFEMA PublicAssistanceFundedProjectsSummaries v1, version 2026-09-29T150754Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/PublicAssistanceFundedProjectsSummaries (API)
  4. FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
  5. FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-30, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
  6. NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-30, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
  7. NOAA National Weather Service, NWS county-public forecast zones correlation file, version bp03mr20 to bp16ap26 (11 files; newest bp16ap26), pulled 2026-09-30, https://www.weather.gov/gis/ZoneCounty
  8. U.S. Census Bureau, Census 2024 Gazetteer, 2020 place by county, CT county-to-cousub crosswalk, version 2024-gazetteer, pulled 2026-09-30, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_counties_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_cousubs_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_place_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_unsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_elsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_scsd_national.zip, https://www2.census.gov/geo/docs/reference/codes2020/national_place_by_county2020.txt, https://www2.census.gov/geo/docs/reference/ct_change/ct_cou_to_cousub_crosswalk.xlsx (used to match place names and codes; no table prints its values)

What this packet is and what the plan adds

This packet is the federal data for the plan's risk assessment (the summary on page 1 says how it is organized); the plan and FEMA's review decide whether each item is met.

The plan adds what only the community has: local data on assets, critical facilities, development and each jurisdiction's impacts; local hazard history, including state-declared emergencies; the mitigation strategy; and adoption.

How the federal data are built: National Risk Index values are FEMA's model, not counts of events. Storm Events is more complete from 1996; zone-level records are placed by forecast zone, not by location in the county. Public Assistance for a jurisdiction is matched by applicant name. The Methods page gives every rule and the known edge cases.

OpenFEMA disclaimer

This product uses the Federal Emergency Management Agency's OpenFEMA API, 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).

Reuse, citation and corrections

Reuse and citation: Hazard Plain text and tables are licensed under Creative Commons Attribution 4.0 International (CC BY 4.0, https://creativecommons.org/licenses/by/4.0/); credit Hazard Plain and the release. The underlying federal data are public domain; OpenFEMA data are also subject to the OpenFEMA terms and conditions.

Cite this: Hazard Plain (2026). Johnson County, IL: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 17087). Automated baseline. https://hazardplain.org/il/17087/ Built from FEMA OpenFEMA, the FEMA National Risk Index and NOAA NCEI Storm Events; source versions in the packet's Sources list.

Corrections: to report an error, name the packet, the table and what your records show. Contact: [email protected]