Hazard Plain Automated baseline

Winnebago County, WI

Risk-assessment baseline packet

County FIPS:
55139
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: Approved, expires 2027-05-08. Plan: Winnebago County (FEMA plan 108189), approved 2022-05-09.

Since the plan was approved on 2022-05-09: 1 new hazard declaration (1 incident) and 61 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): Inland Flooding ($42,822,377 a year), Cold Wave ($14,063,433) and Tornado ($9,373,010).

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:
Approved, expires 2027-05-08
Plan:
Winnebago County (FEMA plan 108189)
Approved:
2022-05-09
Days to expiry:
220
Update underway:
none recorded in FEMA's plan tracker

What changed since your last plan (approved 2022-05-09)

New federal declarations:
1 new hazard declaration (1 incident): DR-4923-WI (Severe Storms, Tornadoes, and Flooding)
Storm Events records since approval:
61 records (data through 2026-06-30)
Repetitive loss now:
FMA RL 0, SRL 0 (44 CFR 77.2); any definition: 12
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: 23 rows, in the section "Plan clock: Plan status for every jurisdiction listed in this county" on the following pages.

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

Plan clock

Plan status for every jurisdiction listed in this county

Source: 1

JurisdictionTypeStatusPlanApprovedExpiresDays to expirynegative = days since expiryUpdate underwayNotes
Winnebago CountyCountyApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220
Appleton cityCityApproved, expires 2029-09-23Outagamie County Hazard Mitigation Plan 2024 (FEMA plan 110142)2024-09-242029-09-231,089Also approved under plan 102339 (Calumet County, expires 2027-06-16); plan 108189 (Winnebago County, expires 2027-05-08). FEMA's plan status map shows one plan per jurisdiction and may show one of these; this packet uses the approved plan that expires last. this jurisdiction approved 2025-04-14
Fox Crossing villageVillageApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220this jurisdiction approved 2022-09-23
Menasha cityCityApproved, expires 2027-06-16Calumet County (FEMA plan 102339)2022-06-172027-06-16259Also approved under plan 108189 (Winnebago County, expires 2027-05-08). FEMA's plan status map shows one plan per jurisdiction and may show one of these; this packet uses the approved plan that expires last.
Neenah cityCityApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220this jurisdiction approved 2022-09-23
Omro cityCityApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220this jurisdiction approved 2022-07-28
Oshkosh cityCityApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220
Winneconne villageVillageApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220this jurisdiction approved 2022-07-28
Algoma townTownApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220this jurisdiction approved 2022-09-23
Black Wolf townTownApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220this jurisdiction approved 2022-09-23
Clayton townTownApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220
Neenah townTownApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220
Nekimi townTownPlan 108189 approved 2022-05-09, pending adoption here; not yet eligibleWinnebago County (FEMA plan 108189), pending adoption here2022-05-09 by FEMA; not yet adopted here2027-05-08 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Nepeuskun townTownPlan 108189 approved 2022-05-09, pending adoption here; not yet eligibleWinnebago County (FEMA plan 108189), pending adoption here2022-05-09 by FEMA; not yet adopted here2027-05-08 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Omro townTownApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220this jurisdiction approved 2022-09-23
Oshkosh townTownApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220
Poygan townTownApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220this jurisdiction approved 2022-07-28
Rushford townTownApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220this jurisdiction approved 2022-07-28
Utica townTownApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220this jurisdiction approved 2022-09-23
Vinland townTownApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220this jurisdiction approved 2022-10-06
Winchester townTownApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220this jurisdiction approved 2022-09-23
Winneconne townTownApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220
Wolf River townTownApproved, expires 2027-05-08Winnebago County (FEMA plan 108189)2022-05-092027-05-08220this jurisdiction approved 2022-09-23

Plan 108189 lists 1 other participant not on this page. Not covered by it yet: Horicon city (Dodge County; approvable pending adoption, not yet adopted).

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
1Inland FloodingRelatively ModerateRelatively Moderate$42,692,827$107,269$22,281$42,822,37720
2Cold WaveRelatively HighRelatively High$166$100$14,063,167$14,063,43313
3TornadoRelatively HighRelatively High$4,106,321$4,913$5,261,775$9,373,01022
4Strong WindRelatively HighRelatively High$726,862$64,157$2,544,286$3,335,304167Includes 12 High Wind and 20 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
5HailRelatively ModerateRelatively High$2,495,778$49,976$349,440$2,895,194112
6Heat WaveRelatively LowRelatively Low$219$1$1,367,691$1,367,91013
7LightningRelatively HighRelatively High$79,374n/a$909,319$988,6939
8Winter WeatherRelatively ModerateRelatively Moderate$10,825$1,029$205,882$217,73684
9EarthquakeVery LowVery Low$88,475n/a$27,038$115,513Storm Events does not record earthquakes.
10Ice StormRelatively LowRelatively Low$2,847n/a$96,448$99,2953
11WildfireVery LowVery Low$27,932$65$3,016$31,0140No recorded events in Storm Events since 1996 (data through 2026-06-30).
12DroughtVery LowVery Lown/a$17,543n/a$17,5439
13HurricaneVery LowVery Low$4,192$1,092under $1$5,2840No recorded events in Storm Events since 1996 (data through 2026-06-30).
14LandslideVery LowVery Low$33n/a$125$1570No 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 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 7 (Very Low, 38.8); tract 14 (Very Low, 17.9); tract 18.03 (Very Low, 17.7)
Hurricanetract 20.02 (Very Low, 26.8); tract 21 (Very Low, 26.6); tract 22.02 (Very Low, 24.6)
Landslidetract 21 (Very Low, 75.0); tract 19 (Very Low, 68.1); tract 16 (Very Low, 64.2)
Tornadotract 18.03 (Relatively High, 91.1); tract 20.02 (Relatively High, 85.6); tract 7 (Relatively High, 85.5)
Wildfiretract 21 (Relatively Low, 80.0); tract 20.02 (Relatively Low, 77.4); tract 22.02 (Relatively Low, 73.6)

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 7 is Census Tract 7). 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 chill13 records, 1996 to 2026 (13 zone-level)1 day to 7 days (median 2 days); 12 with a recorded value7 consecutive days, 1996-01-30 to 1996-02-05, zone-levelCountywide (zone-level records).
Frost/Freeze (outside NRI's Cold Wave definition)crop damage0
DroughtU.S. Drought Monitor scale (D0 to D4)9 records, 1999 to 2023 (9 zone-level)7 days to 108 days (median 22 days); 5 with a recorded value108 days (about 3.5 months), 2023-07-01 to 2023-10-16, a run of 4 consecutive Storm Events drought records, zone-levelCountywide (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)143 records, 1964 to 20260.75 in to 4.25 in (median 1 in); 143 with a recorded value4.25 in hail, 2011-05-22Hail, 2000-05-12, $10,400,000 property; crops not reported (2000 dollars)Event records naming jurisdictions in the plan: Oshkosh city (30 records), Oshkosh town (30 records), Menasha city (19 records), Winchester town (14 records), Neenah city (10 records), Neenah town (10 records), Omro city (5 records), Omro town (5 records), Appleton city (1 record).
Excessive Heat, Heatheat index (in event narratives)13 records, 1998 to 2026 (13 zone-level)1 day to 9 days (median 2 days); 7 with a recorded value9 consecutive days, 1999-07-23 to 1999-07-31, 1 direct death, 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)3 records, 1996 to 2013 (3 zone-level)No damage reported in 3 records.Countywide (zone-level records).
Flash Flood, Flood, Lakeshore Flooddamage and flood days (flood depth: FIRM)20 records, 1996 to 2026 (6 zone-level)Flash Flood, 2008-06-12, $18,600,000 property; $4,500,000 crops (2008 dollars)Event records naming jurisdictions in the plan: Oshkosh city (5 records), Oshkosh town (5 records), Menasha city (3 records), Appleton city (1 record), Neenah city (1 record), Neenah town (1 record), Omro city (1 record), Omro town (1 record), Winneconne town (1 record), Winneconne village (1 record). Zone-level records (6) 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)9 records, 1997 to 2018Lightning, 2012-05-03, $750,000 property; $0 crops (2012 dollars)Event records naming jurisdictions in the plan: Oshkosh city (3 records), Oshkosh town (3 records), Neenah city (2 records), Neenah town (2 records), Menasha city (1 record).Storm Events lists lightning with damage or casualties.
High Wind and Strong Wind (outside NRI's Strong Wind definition)wind speed (kt and mph)32 records, 1996 to 2025 (32 zone-level)39 kt (45 mph) to 63 kt (72 mph) (median 50 kt (58 mph)); 17 with a recorded value63 kt (72 mph), measurement type not recorded, High Wind, 1998-11-10; NWS zone WIZ048Countywide (zone-level records).
Thunderstorm Windwind speed (kt and mph)193 records, 1964 to 202643 kt (49 mph) to 87 kt (100 mph) (median 52 kt (60 mph)); 155 with a recorded value87 kt (100 mph) estimated gust, Thunderstorm Wind, 2011-04-10Event records naming jurisdictions in the plan: Oshkosh city (40 records), Oshkosh town (40 records), Neenah city (24 records), Neenah town (24 records), Omro city (14 records), Omro town (14 records), Menasha city (11 records), Winneconne town (8 records), Winneconne village (8 records), Winchester town (7 records); and 1 more jurisdiction (see the Excel file).
TornadoEnhanced Fujita (Fujita before Feb 2007)31 records, 1959 to 2020F/EF0 to F/EF4 (median F/EF0); 30 with a recorded valueF4 tornado, 1974-04-21, 13.5 mi path length (whole path, pre-1996), 200 yd wide, $2,500,000 property; crops not recorded (1974 dollars), 35 direct injuriesEvent records naming jurisdictions in the plan: Oshkosh city (4 records), Oshkosh town (4 records), Winchester town (4 records), Menasha city (2 records), Winneconne town (2 records), Winneconne village (2 records), Appleton city (1 record), Neenah city (1 record), Neenah town (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)84 records, 1996 to 2026 (84 zone-level)No damage reported in 84 records.Countywide (zone-level records).

Where a hazard names more than 10 jurisdictions, the table lists the 10 with the most records; every one is in the Excel file, sheet "B1-c Extent".

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.

Supports FEMA checklist item B1-d: previous occurrences

Federal declarations for this county: 11 declarations covering 8 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
2026-06-302026-04-13DR-4923-WIMajor disasterSevere Storms, Tornadoes, and FloodingInland Flooding (primary); also designated: TornadoPA not declared for this countynew since last plan; within last 5 years
2020-04-042020-01-20DR-4520-WIMajor disasterCOVID-19 PandemicNon-natural, not counted$207,533.92
2020-03-132020-01-20EM-3454-WIEmergencyCOVID-19Non-natural, not countedno Public Assistance recordedsame incident as DR-4520
2008-06-142008-06-05DR-1768-WIMajor disasterSevere Storms, Tornadoes, and FloodingInland Flooding; Tornado$968,644.36
2005-09-132005-08-29EM-3249-WIEmergencyHurricane Katrina EvacuationHurricane: evacuation support, not a local hazard event; not countedno Public Assistance recorded
2004-06-182004-05-07DR-1526-WIMajor disasterSevere Storms and FloodingInland Flooding$625,751.21
2001-05-112001-04-10DR-1369-WIMajor disasterFlooding, Severe Storms and TornadoesInland Flooding (primary); also designated: Tornado, Winter Weather$1,950,273.58
1993-07-021993-06-07DR-994-WIMajor disasterSevere Storms, Tornadoes & FloodingInland Flooding; TornadoPA not declared for this county
1990-07-131990-06-22DR-874-WIMajor disasterSevere Storms, Tornadoes & FloodingInland Flooding; TornadoPA not declared for this county
1976-06-171976-06-17EM-3014-WIEmergencyDroughtDroughtno Public Assistance recorded
1974-04-261974-04-26DR-431-WIMajor disasterTornadoesTornadono 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.

Public Assistance not placed in any Wisconsin county: 1 row, $87,788.41; listed on the Wisconsin 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 Wave13404001996 to 2026-06-30
Drought9404101996 to 2026-06-30
Earthquake000000Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail143626001955 to 2026-06-30
Heat Wave13303001996 to 2026-06-30
Hurricane0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Ice Storm3000001996 to 2026-06-30
Inland Flooding20303611996 to 2026-06-30
Landslide0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Lightning9000001996 to 2026-06-30
Strong Wind22528729001955 to 2026-06-30Includes 12 High Wind and 20 Strong Wind records.
Tornado31000611950 to 2026-06-30
Wildfire0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Winter Weather8413215101996 to 2026-06-30

Notable Storm Events records

Sources: 1, 6, 7

DateEvent typeMagnitude or extentDamagenominal dollarsDeaths, injuriesdirect onlyLocationFlagsWhy listed
2023-07-01Drought$0 property; crops not reported (zone total, 2023 dollars)0, 0NWS zone WIZ048 (WINNEBAGO), zone-levelnew since last plan; within last 5 yearsB1-c worst recorded: Drought
2020-06-02Thunderstorm Wind50 kt (58 mph) estimated gust$0 property; $0 crops (2020 dollars)1, 0LAKE BUTTE DES MORTSdeaths or injuries recorded
2012-05-03Lightning$750,000 property; $0 crops (2012 dollars)0, 0FISKB1-c worst recorded: Lightning
2011-05-22Hail4.25 in$5,000 property; crops not reported (2011 dollars)0, 0WINCHESTERB1-c worst recorded: Hail
2011-04-10Thunderstorm Wind87 kt (100 mph) estimated gust$5,000,000 property; crops not reported (2011 dollars)0, 0NEENAH to MENASHAB1-c worst recorded: Thunderstorm Wind
2008-06-12Flash Flood$18,600,000 property; $4,500,000 crops (2008 dollars)0, 0OSHKOSH to WINNEBAGOB1-c worst recorded: Flash Flood, Flood, Lakeshore Flood
2003-11-12Strong Wind41 kt (47 mph) measured gustdamage not reported2, 0NWS zone WIZ048 (WINNEBAGO), zone-leveldeaths or injuries recorded
1999-07-23Heatdamage not reported1, 0NWS zone WIZ048 (WINNEBAGO), zone-levelB1-c worst recorded: Excessive Heat, Heat
1998-11-10High Wind63 kt (72 mph), measurement type not recorded$115,000 property; crops not reported (zone total, 1998 dollars)0, 0NWS zone WIZ048 (WINNEBAGO), zone-levelB1-c worst recorded: High Wind and Strong Wind
1996-01-30Cold/Wind Chilldamage not reported0, 0NWS zone WIZ048 (WINNEBAGO), zone-levelB1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill
1984-04-27TornadoF4, 12 mi path length (whole path, pre-1996), 60 yd wide$2,500,000 property; crops not recorded (1984 dollars)1, 10location not recordeddeaths or injuries recorded
1974-04-21TornadoF4, 13.5 mi path length (whole path, pre-1996), 200 yd wide$2,500,000 property; crops not recorded (1974 dollars)0, 35location not recordedB1-c worst recorded: Tornado

The full list is in the Excel file, sheet "B1-d Storm Events history" (550 rows).

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

1 Fire Management declaration (1980-04-24 to 1980-04-24) FEMA filed as Statewide with no county; each names one local fire. Listed on the state page.

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

Tribal and special-area declarations in this state are listed on the state page.

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 Wave5.74event-days per yearabout 5.74 days per yearLikelyStorm Events event-days in 8 of 30 years, 1996 to 2025 (26.7%)1092005-11-12 to 2024-11-12 (19 years)countywide
Drought0.687event-days per yearabout 0.687 days per yearLikelyStorm Events event-days in 4 of 30 years, 1996 to 2025 (13.3%)492000 to 2025 (25.25 years; D3 and D4 only)countywide
Earthquake0.000457annual probability at a locationchance a given location in the county has at least minor-damage shaking in a year: 0.0457%not shownmodeledsee B1-fNo descriptor (Storm Events does not record earthquakes).
Hail2.78events per yearabout 2.78 per yearHighly likelyFEMA annualized frequency (modeled)103.5 (modeled)1986 to 2023 (38 years)countywide
Heat Wave1.63event-days per yearabout 1.63 days per yearLikelyStorm Events event-days in 7 of 30 years, 1996 to 2025 (23.3%)242005-11-12 to 2024-11-12 (19 years)countywide
Hurricane0.01events per yearabout 1 in 100 yearsPossibleFEMA annualized frequency (modeled)01851 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 Storm0.274event-days per yearabout 0.274 days per yearLikelyStorm Events event-days in 3 of 30 years, 1996 to 2025 (10%)191946-12-31 to 2014-02-12 (67 years)countywide
Inland Flooding0.571event-days per yearabout 0.571 days per yearLikelyStorm Events event-days in 11 of 30 years, 1996 to 2025 (36.7%)161996 to 2023 (28 years)see B1-f
Landslide0.0476events per year (modeled)about 1 in 21 yearsPossibleFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Lightning34.2days per year with a strikeabout 34.2 days per yearHighly likelyFEMA annualized frequency (modeled)not shown1995 to 2023 (29 years; CONUS)countywide
Strong Wind2.96events per yearabout 2.96 per yearHighly likelyFEMA annualized frequency (modeled)1111986 to 2023 (38 years)countywide
Tornado0.339events per yearabout 1 in 3 yearsLikelyFEMA annualized frequency (modeled)not shown1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)see B1-f
Wildfire0.000302annual probability at a locationchance a given location in the county burns in a year: 0.0302%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 Weather15.6event-days per yearabout 15.6 days per yearHighly likelyStorm Events event-days in 28 of 30 years, 1996 to 2025 (93.3%)2972005-11-12 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 202553301.77
Hail2.00 in+1996 to 20256300.2
Thunderstorm Wind (counted as NRI Strong Wind)50-64 kt1996 to 2025115303.83
Thunderstorm Wind (counted as NRI Strong Wind)65 kt+1996 to 202510300.333
Thunderstorm Wind (counted as NRI Strong Wind)unmeasured or below 50 kt1996 to 20257300.233
TornadoEF0-11996 to 202522300.733
TornadoEF2-31996 to 20250300
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 Wave45 of 4568.988.396.3Very High 1, Relatively High 38, Relatively Moderate 6
Drought2 of 4581.585.489.2Relatively Low 2, No Rating 43
Earthquake45 of 451.49.038.8Very Low 45
Hail45 of 4564.782.692.9Relatively High 9, Relatively Moderate 35, Relatively Low 1
Heat Wave45 of 4513.737.761.5Relatively Moderate 1, Relatively Low 42, Very Low 2
Hurricane45 of 4514.118.426.8Very Low 45
Ice Storm45 of 459.025.144.8Relatively Low 8, Very Low 37
Inland Flooding45 of 4516.658.497.6Very High 1, Relatively High 10, Relatively Moderate 18, Relatively Low 16
Landslide34 of 459.031.875.0Very Low 34, No Rating 11
Lightning45 of 4536.966.387.8Relatively High 6, Relatively Moderate 33, Relatively Low 6
Strong Wind45 of 4558.383.593.9Relatively High 26, Relatively Moderate 19
Tornado45 of 4549.572.091.1Relatively High 17, Relatively Moderate 27, Relatively Low 1
Wildfire34 of 4519.036.880.0Relatively Low 9, Very Low 25, No Rating 11
Winter Weather45 of 4540.262.178.9Relatively High 1, Relatively Moderate 39, Relatively Low 5

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 planNotes
Winnebago CountyCountyApproved, expires 2027-05-08FMA RL 0, SRL 0; any 2no Public Assistance recorded0 total; 0 since its plan
Appleton cityCityApproved, expires 2029-09-23FMA RL 0, SRL 1; any 1no Public Assistance recorded3 total; 1 since its planAlso approved under plan 102339 (Calumet County, expires 2027-06-16); plan 108189 (Winnebago County, expires 2027-05-08). FEMA's plan status map shows one plan per jurisdiction and may show one of these; this packet uses the approved plan that expires last. Whole community, including the part in Outagamie County; none of its repeat-flood properties are in this county.
Fox Crossing villageVillageApproved, expires 2027-05-08FMA RL 0, SRL 0; any 0$10,707.230 total; 0 since its planIncludes $10,707.23 for declarations not counted as hazard incidents (DR-4520-WI).
Menasha cityCityApproved, expires 2027-06-16FMA RL 0, SRL 0; any 0$104,162.9836 total; 1 since its planAlso approved under plan 108189 (Winnebago County, expires 2027-05-08). FEMA's plan status map shows one plan per jurisdiction and may show one of these; this packet uses the approved plan that expires last.
Neenah cityCityApproved, expires 2027-05-08FMA RL 0, SRL 0; any 1$161,238.8538 total; 4 since its plan
Omro cityCityApproved, expires 2027-05-08FMA RL 0, SRL 0; any 0$70,065.6020 total; 2 since its plan
Oshkosh cityCityApproved, expires 2027-05-08FMA RL 0, SRL 0; any 9$1,422,459.5482 total; 9 since its plan
Winneconne villageVillageApproved, expires 2027-05-08FMA RL 0, SRL 0; any 0$108,846.7811 total; 2 since its plan
Algoma townTownApproved, expires 2027-05-08$84,573.580 total; 0 since its planNo NFIP community ID on this jurisdiction's plan row.
Black Wolf townTownApproved, expires 2027-05-08$14,797.250 total; 0 since its planNo NFIP community ID on this jurisdiction's plan row.
Clayton townTownApproved, expires 2027-05-08$24,667.470 total; 0 since its planNo NFIP community ID on this jurisdiction's plan row.
Neenah townTownApproved, expires 2027-05-08$2,757.3338 total; 4 since its planNo NFIP community ID on this jurisdiction's plan row.
Nekimi townTownPlan 108189 approved 2022-05-09, pending adoption here; not yet eligible$14,487.070 total; no approved planNo NFIP community ID on this jurisdiction's plan row.
Nepeuskun townTownPlan 108189 approved 2022-05-09, pending adoption here; not yet eligibleno Public Assistance recorded0 total; no approved planNo NFIP community ID on this jurisdiction's plan row.
Omro townTownApproved, expires 2027-05-08$20,215.8120 total; 2 since its planNo NFIP community ID on this jurisdiction's plan row.
Oshkosh townTownApproved, expires 2027-05-08$43,364.8682 total; 9 since its planNo NFIP community ID on this jurisdiction's plan row.
Poygan townTownApproved, expires 2027-05-08no Public Assistance recorded1 total; 0 since its planNo NFIP community ID on this jurisdiction's plan row.
Rushford townTownApproved, expires 2027-05-08$6,718.730 total; 0 since its planNo NFIP community ID on this jurisdiction's plan row.
Utica townTownApproved, expires 2027-05-08$18,358.940 total; 0 since its planNo NFIP community ID on this jurisdiction's plan row.
Vinland townTownApproved, expires 2027-05-08$10,218.730 total; 0 since its planNo NFIP community ID on this jurisdiction's plan row.
Winchester townTownApproved, expires 2027-05-08$14,321.5025 total; 2 since its planNo NFIP community ID on this jurisdiction's plan row.
Winneconne townTownApproved, expires 2027-05-08$67,403.8411 total; 2 since its planNo NFIP community ID on this jurisdiction's plan row.
Wolf River townTownApproved, expires 2027-05-08$1,802.250 total; 0 since its planNo NFIP community ID on this jurisdiction's plan row.

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 2022-05-09county-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$44,308,101,627$157,381,229171,623$166$100$14,063,167under 0.0001%$0
Droughtn/a$7,077,096n/an/a$17,543n/a0.248% (agriculture)$0NRI has no building exposure for this hazard; agriculture shown
Earthquake$77,265,765,735n/a171,730$88,475n/a$27,0380.000115%
Hail$44,308,101,627$157,381,229171,623$2,495,778$49,976$349,4400.00563%$0
Heat Wave$44,308,101,627$157,381,229171,623$219$1$1,367,691under 0.0001%$0
Hurricane$44,308,101,627$157,381,229171,623$4,192$1,092under $1under 0.0001%
Ice Storm$44,162,830,186n/a171,174$2,847n/a$96,448under 0.0001%
Inland Flooding$44,202,021,083$10,424,0584,238$42,692,827$107,269$22,281n/a (see note)$0no Public Assistance recorded (1 declaration)NRI 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$43,540,529n/a153$33n/a$125under 0.0001%
Lightning$44,308,101,627n/a171,623$79,374n/a$909,3190.000179%
Strong Wind$44,308,101,627$157,381,229171,623$726,862$64,157$2,544,2860.00164%$0$0
Tornado$44,308,101,627$157,381,229171,623$4,106,321$4,913$5,261,7750.00927%no Public Assistance recorded (1 declaration)
Wildfire$1,799,842,645$26,189,8499,191$27,932$65$3,0160.00155%
Winter Weather$44,308,101,627$157,381,229171,623$10,825$1,029$205,882under 0.0001%$0

Totals since 2022-05-09 (Storm Events through 2026-06-30): 34 county-coded records, 34 with a damage value recorded (including $0), $0; 27 zone-level records, 27 with a damage value recorded (including $0), $0 reported for the zone; Public Assistance: none recorded on the 1 counted declaration.

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
Population171,623
Building value (total, not at risk)$44,308,101,627
Agriculture value (total, not at risk)$157,381,229
NRI risk rating (all hazards)Relatively Moderate
Expected annual loss, buildings and agriculture, all hazards$50,481,994
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)$24,850,467
Social vulnerability ratingRelatively Low
Community resilience ratingVery High
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 definition12Severe 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 total001201202
of which: Neenah city0010101
of which: Oshkosh city0090901
of which: Winnebago County (unincorporated area)0020200
Statewide, no county in FEMA's file0020200

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 insuredpropertiesNote
Winnebago County5505370020200
Appleton city5555420111101Whole community, including the part in Outagamie County; none of its repeat-flood properties are in this county.
Fox Crossing village5506380000000
Menasha city5505100000000
Neenah city5505090010101
Omro city5505330000000
Oshkosh city5505110090901
Winneconne village5505120000000

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

Sources: 1, 4

Occupancy groupRL, FMApropertiesSRL, FMApropertiesRL, NFIPpropertiesSRL, NFIPpropertiesAny categorypropertiesMitigatedpropertiesCurrently insuredproperties
single-family residential001001002
2 to 4 unit residential0000000
other residential0000000
non-residential0020200
not reported0000000

FEMA's occupancy groups have no institutional class; institutional properties are counted in non-residential or other residential in the table by occupancy group.

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 12 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). Winnebago County, WI: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 55139). Automated baseline. https://hazardplain.org/wi/55139/ 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: contact@hazardplain.org