Hazard Plain Automated baseline

St. Croix County, WI

Risk-assessment baseline packet

County FIPS:
55109
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 2029-02-25. Plan: St. Croix County HMP Update (FEMA plan 109613), approved 2024-02-26.

Since the plan was approved on 2024-02-26: no new hazard declaration and 52 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 ($15,740,246 a year), Tornado ($7,904,943) and Cold Wave ($4,427,904).

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 2029-02-25
Plan:
St. Croix County HMP Update (FEMA plan 109613)
Approved:
2024-02-26
Days to expiry:
879

What changed since your last plan (approved 2024-02-26)

New federal declarations:
none
Storm Events records since approval:
52 records (data through 2026-06-30)
Repetitive loss now:
FMA RL 0, SRL 0 (44 CFR 77.2); any definition: 3
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: 19 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
St. Croix CountyCountyApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16
Baldwin villageVillageApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16
Deer Park villageVillageApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16
Glenwood City cityCityApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16
Hammond villageVillageApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16
Hudson cityCityApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16
New Richmond cityCityApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16
North Hudson villageVillageApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879
River Falls cityCityPlan 110709 approved 2025-04-22, pending adoption here; not yet eligiblePierce County Hazard Mitigation Plan 2025 (FEMA plan 110709), pending adoption here2025-04-22 by FEMA; not yet adopted here2030-04-21 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Roberts villageVillageApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16
Somerset villageVillageApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16
Spring Valley villageVillagePlan 110709 approved 2025-04-22, pending adoption here; not yet eligiblePierce County Hazard Mitigation Plan 2025 (FEMA plan 110709), pending adoption here2025-04-22 by FEMA; not yet adopted here2030-04-21 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Star Prairie villageVillageApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16
Woodville villageVillageApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16
Amery School DistrictSchool/School DistrictPlan 110723 approved 2025-04-30, pending adoption here; not yet eligiblePolk County Hazard Mitigation Plan 2025 (FEMA plan 110723), pending adoption here2025-04-30 by FEMA; not yet adopted here2030-04-29 once adoptedFEMA tracker shows a plan approvable pending adoptionNot yet eligible: adopt the approved plan.
Hudson School DistrictSchool/School DistrictApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16
Osceola School DistrictSchool/School DistrictApproved, expires 2030-04-29Polk County Hazard Mitigation Plan 2025 (FEMA plan 110723)2025-04-302030-04-291,307this jurisdiction approved 2025-08-27
Northwood Technical CollegeCollege/UniversityApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16
St. Croix Electric CooperativeElectric/Power AuthorityApproved, expires 2029-02-25St. Croix County HMP Update (FEMA plan 109613)2024-02-262029-02-25879this jurisdiction approved 2024-10-16

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 2026-06-30countWhy this hazard can be left outNRI Not Applicable, no declaration and no Storm Events record since 1996Storm Events coverage note
1Inland FloodingRelatively LowRelatively Moderate$15,361,646$36,538$342,063$15,740,24619
2TornadoRelatively ModerateRelatively Moderate$3,854,680$5,047$4,045,215$7,904,94316
3Cold WaveRelatively ModerateRelatively High$85$1,311$4,426,508$4,427,90419Includes 1 Frost/Freeze record (outside NRI's Cold Wave definition; counted in this table and in B1-d, not in the B1-e descriptor).
4Strong WindRelatively HighRelatively High$2,647,430$220,816$1,055,523$3,923,769131Includes 3 High Wind and 2 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
5HailRelatively ModerateRelatively Moderate$1,918,325$213,670$107,878$2,239,873162
6LightningRelatively ModerateRelatively High$62,443n/a$880,714$943,15710
7Heat WaveRelatively LowRelatively Low$1,032$2$538,908$539,94310
8Winter WeatherRelatively ModerateRelatively Moderate$24,089$1,372$144,223$169,684103
9Ice StormRelatively LowRelatively Low$3,839n/a$58,261$62,1003
10WildfireVery LowVery Low$47,185$39$5,935$53,1590No recorded events in Storm Events since 1996 (data through 2026-06-30).
11EarthquakeVery LowVery Low$8,348n/a$2,080$10,427Storm Events does not record earthquakes.
12LandslideRelatively LowVery Low$1,019n/a$6,843$7,8620Declared 1 time; no Storm Events record of this type.
13DroughtVery LowVery Lown/a$152n/a$1520Declared 1 time; no Storm Events record of this type.
HurricaneNot ApplicableNot Applicable0NRI rates hurricane Not Applicable for this county, and no counted federal declaration for this county names it (EM-3249-WI names it but is not counted as a local occurrence; see B1-d).No 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 1205.01 (Very Low, 6.6); tract 1209.05 (Very Low, 5.9); tract 1205.02 (Very Low, 5.3)
Hurricaneno tract has a National Risk Index rating for this hazard
Landslidetract 1207 (Relatively Low, 95.0); tract 1209.06 (Relatively Low, 91.6); tract 1204.01 (Relatively Low, 91.5)
Tornadotract 1209.05 (Very High, 98.3); tract 1205.01 (Very High, 94.7); tract 1202.01 (Very High, 93.9)
Wildfiretract 1202.02 (Relatively Low, 83.4); tract 1209.06 (Relatively Low, 80.6); tract 1204.01 (Relatively Low, 80.5)

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 1205.01 is Census Tract 1205.01). 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 chill18 records, 1996 to 2026 (18 zone-level)1 day to 5 days (median 2 days); 16 with a recorded value5 consecutive days, 1996-01-31 to 1996-02-04, zone-levelCountywide (zone-level records).
Frost/Freeze (outside NRI's Cold Wave definition)crop damage1 record, 2004 (1 zone-level)No crop damage reported in 1 record.Countywide (zone-level records).
DroughtU.S. Drought Monitor scale (D0 to D4)0Storm 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)182 records, 1975 to 20260.75 in to 4.5 in (median 1 in); 182 with a recorded value4.5 in hail, 1988-06-19Hail, 2001-05-01, $3,000,000 property; crops not reported (2001 dollars)Event records naming jurisdictions in the plan: New Richmond city (21 records), River Falls city (19 records), Hammond village (16 records), Hudson city (16 records), Baldwin village (14 records), Roberts village (12 records), Star Prairie village (12 records), Glenwood City city (11 records), Somerset village (10 records), North Hudson village (5 records); and 2 more jurisdictions (see the Excel file).
Excessive Heat, Heatheat index (in event narratives)10 records, 1999 to 2023 (10 zone-level)1 day to 5 days (median 2 days); 9 with a recorded value5 consecutive days, 2001-08-04 to 2001-08-08, zone-levelCountywide (zone-level records).
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 1998 (3 zone-level)No damage reported in 3 records.Countywide (zone-level records).
Flash Flood, Flood, Lakeshore Flooddamage and flood days (flood depth: FIRM)19 records, 1997 to 2020 (3 zone-level)Flash Flood, 2020-06-29, $8,000,000 property; $0 crops (2020 dollars), 1 direct deathEvent records naming jurisdictions in the plan: River Falls city (6 records), Baldwin village (3 records), Hudson city (3 records), Roberts village (3 records), Woodville village (2 records), Deer Park village (1 record). Zone-level records (3) 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)10 records, 2000 to 2017Lightning, 2000-08-12, damage not reported, 1 direct death, 2 direct injuriesLightning, 2012-05-26, $750,000 property; $0 crops (2012 dollars)Event records naming jurisdictions in the plan: Hudson city (3 records), Somerset village (3 records), New Richmond city (1 record), Roberts village (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)5 records, 1996 to 2021 (5 zone-level)35 kt (40 mph) to 53 kt (61 mph) (median 50 kt (58 mph)); 5 with a recorded value53 kt (61 mph) measured, High Wind, 2001-04-07; NWS zone WIZ023Strong Wind, 2021-09-17, $200 property; $0 crops (zone total, 2021 dollars)Countywide (zone-level records).
Thunderstorm Windwind speed (kt and mph)171 records, 1966 to 202548 kt (55 mph) to 85 kt (98 mph) (median 52 kt (60 mph)); 135 with a recorded value85 kt (98 mph), measurement type not recorded, Thunderstorm Wind, 1996-05-19Thunderstorm Wind, 2007-08-13, $35,000,000 property; $10,000,000 crops (2007 dollars)Event records naming jurisdictions in the plan: Hudson city (27 records), New Richmond city (14 records), Somerset village (13 records), Deer Park village (11 records), River Falls city (9 records), Star Prairie village (9 records), Baldwin village (8 records), Roberts village (8 records), Glenwood City city (7 records), Hammond village (7 records); and 2 more jurisdictions (see the Excel file).
TornadoEnhanced Fujita (Fujita before Feb 2007)34 records, 1953 to 2025F/EF0 to F/EF5 (median between F/EF0 and F/EF1); 34 with a recorded valueF5 tornado, 1958-06-04, 8.6 mi path length (whole path, pre-1996), 880 yd wide, $25,000,000 property; crops not recorded (1958 dollars), 1 direct death, 20 direct injuriesEvent records naming jurisdictions in the plan: Hammond village (5 records), New Richmond city (2 records), Somerset village (2 records), Woodville village (2 records), Hudson city (1 record), Roberts village (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)103 records, 1996 to 2026 (103 zone-level)Winter Storm, 2010-12-10, $200,000 property; $0 crops (2010 dollars), 1 direct death (reported for the zone); NWS zone WIZ023Countywide (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 dollarsNotes
2020-04-042020-01-20DR-4520-WIMajor disasterCOVID-19 PandemicNon-natural, not counted$735,953.65
2020-03-132020-01-20EM-3454-WIEmergencyCOVID-19Non-natural, not countedno Public Assistance recordedsame incident as DR-4520
2013-08-082013-06-20DR-4141-WIMajor disasterSevere Storms, Flooding, and MudslidesInland Flooding; Landslide$334,157.39
2005-09-132005-08-29EM-3249-WIEmergencyHurricane Katrina EvacuationHurricane: evacuation support, not a local hazard event; not countedno Public Assistance recorded
2002-09-102002-09-02DR-1432-WIMajor disasterSevere Storms, Tornadoes and FloodingTornado (primary); also designated: Inland FloodingPA not declared for this county
2001-05-112001-04-10DR-1369-WIMajor disasterFlooding, Severe Storms and TornadoesInland Flooding (primary); also designated: Tornado, Winter Weather$112,782.53
1998-07-241998-06-18DR-1236-WIMajor disasterSevere Storms,Straigh Line Winds, Tornadoes,Rain,and FloodiInland Flooding; Tornadono Public Assistance recorded
1993-07-021993-06-07DR-994-WIMajor disasterSevere Storms, Tornadoes & FloodingInland Flooding; Tornadono Public Assistance recorded
1976-06-171976-06-17EM-3014-WIEmergencyDroughtDroughtno Public Assistance recorded
1969-05-011969-05-01DR-260-WIMajor disasterFloodingInland Floodingno Public Assistance recorded
1965-04-211965-04-21DR-192-WIMajor disasterTornadoes, Severe Storms & FloodingTornado (primary); also designated: Inland Floodingno Public Assistance recorded

School districts and special districts in this county: $11,000.49 (included in the county total above). Public Assistance matched by applicant name to the school districts and special districts FEMA lists as plan participants in this county. They have no row of their own in the jurisdiction table, so their total is listed here. These dollars are already included in the county PA column of the declarations table (the FEMA record places each applicant in this county), so this line is not added to it.

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 Wave19303001996 to 2026-06-30Includes 1 Frost/Freeze record.
Drought0000101996 to 2026-06-30No Storm Events records of this type; 1 federal declared incident (see declarations table)
Earthquake000000Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail182181755001955 to 2026-06-30
Heat Wave10022001996 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 Flooding19000701996 to 2026-06-30
Landslide0000101996 to 2026-06-30No Storm Events records of this type; 1 federal declared incident (see declarations table)
Lightning10000001996 to 2026-06-30
Strong Wind17612618001955 to 2026-06-30Includes 3 High Wind and 2 Strong Wind records.
Tornado34202501950 to 2026-06-30
Wildfire0000001996 to 2026-06-30No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Winter Weather10317530101996 to 2026-06-30

Notable Storm Events records

Sources: 1, 6, 7

DateEvent typeMagnitude or extentDamagenominal dollarsDeaths, injuriesdirect onlyLocationWhy listed
2021-09-17Strong Wind48 kt (55 mph) estimated gust$200 property; $0 crops (zone total, 2021 dollars)0, 0NWS zone WIZ023 (ST. CROIX), zone-levelB1-c most damaging: High Wind and Strong Wind
2020-06-29Flash Flood$8,000,000 property; $0 crops (2020 dollars)1, 0DEER PARK to RIVER FALLSB1-c worst recorded: Flash Flood, Flood, Lakeshore Flood
2010-12-10Winter Storm$200,000 property; $0 crops (zone total, 2010 dollars)1, 0NWS zone WIZ023 (ST. CROIX), zone-levelB1-c worst recorded: Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet
2007-08-13Thunderstorm Wind78 kt (90 mph) estimated gust$35,000,000 property; $10,000,000 crops (2007 dollars)0, 0NEW RICHMOND to GLENWOOD CITYB1-c most damaging: Thunderstorm Wind
2001-08-04Heatdamage not reported0, 0NWS zone WIZ023 (ST. CROIX), zone-levelB1-c worst recorded: Excessive Heat, Heat
2001-04-07High Wind53 kt (61 mph) measureddamage not reported0, 0NWS zone WIZ023 (ST. CROIX), zone-levelB1-c worst recorded: High Wind and Strong Wind
2000-08-12Lightningdamage not reported1, 2SOMERSETdeaths or injuries recorded
1996-05-19Thunderstorm Wind85 kt (98 mph), measurement type not recorded$2,500,000 property; crops not reported (1996 dollars)0, 0HUDSONB1-c worst recorded: Thunderstorm Wind
1996-01-31Cold/Wind Chilldamage not reported0, 0NWS zone WIZ023 (ST. CROIX), zone-levelB1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill
1988-06-19Hail4.5 indamage not recorded (pre-1996 record)0, 0location not recordedB1-c worst recorded: Hail
1958-06-04TornadoF5, 8.6 mi path length (whole path, pre-1996), 880 yd wide$25,000,000 property; crops not recorded (1958 dollars)1, 20location not recordeddeaths or injuries recorded
1953-05-10TornadoF2, 28.3 mi path length (whole path, pre-1996), 100 yd wide$2,500,000 property; crops not recorded (1953 dollars)1, 9location not recordeddeaths or injuries recorded

The full list is in the Excel file, sheet "B1-d Storm Events history" (556 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 Wave9.05event-days per yearabout 9.05 days per yearLikelyStorm Events event-days in 9 of 30 years, 1996 to 2025 (30%)1722005-11-12 to 2024-11-12 (19 years)countywide
Drought1.82event-days per yearabout 1.82 days per yearStorm Events event-days in 0 of 30 years, 1996 to 2025 (0%)1052000 to 2025 (25.25 years; D3 and D4 only)countywideNo Storm Events drought record, 1996 to 2025
Earthquake0.000249annual probability at a locationchance a given location in the county has at least minor-damage shaking in a year: 0.0249%not shownmodeledsee B1-fNo descriptor (Storm Events does not record earthquakes).
Hail5.31events per yearabout 5.31 per yearHighly likelyFEMA annualized frequency (modeled)201.8 (modeled)1986 to 2023 (38 years)countywide
Heat Wave3.16event-days per yearabout 3.16 days per yearLikelyStorm Events event-days in 6 of 30 years, 1996 to 2025 (20%)532005-11-12 to 2024-11-12 (19 years)countywide
Hurricaneevents per year1851 to 2024 (Atlantic)see B1-fNot Applicable in NRI for this county; no descriptor.
Ice Storm0.334event-days per yearabout 0.334 days per yearPossibleStorm Events event-days in 2 of 30 years, 1996 to 2025 (6.67%)231946-12-31 to 2014-02-12 (67 years)countywide
Inland Flooding0.464event-days per yearabout 0.464 days per yearLikelyStorm Events event-days in 9 of 30 years, 1996 to 2025 (30%)131996 to 2023 (28 years)see B1-f
Landslide0.133events per year (modeled)about 1 in 8 yearsLikelyFEMA annualized frequency (modeled)not shownmodeledsee B1-f
Lightning34.9days per year with a strikeabout 34.9 days per yearHighly likelyFEMA annualized frequency (modeled)not shown1995 to 2023 (29 years; CONUS)countywide
Strong Wind3.95events per yearabout 3.95 per yearHighly likelyFEMA annualized frequency (modeled)1511986 to 2023 (38 years)countywide
Tornado0.429events per yearabout 1 in 2 yearsLikelyFEMA annualized frequency (modeled)not shown1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)see B1-f
Wildfire0.000127annual probability at a locationchance a given location in the county burns in a year: 0.0127%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 Weather17.1event-days per yearabout 17.1 days per yearHighly likelyStorm Events event-days in 28 of 30 years, 1996 to 2025 (93.3%)3252005-11-12 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 2025100303.33
Hail2.00 in+1996 to 202510300.333
Thunderstorm Wind (counted as NRI Strong Wind)50-64 kt1996 to 2025116303.87
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 20251300.0333
TornadoEF0-11996 to 202515300.5
TornadoEF2-31996 to 20251300.0333
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 Wave18 of 1855.981.692.4Relatively High 12, Relatively Moderate 6
Drought12 of 1866.868.671.2Very Low 12, No Rating 6
Earthquake18 of 180.42.86.6Very Low 18
Hail18 of 1873.191.095.1Relatively High 13, Relatively Moderate 5
Heat Wave18 of 189.732.955.7Relatively Low 16, Very Low 2
Hurricane0 of 18Not Applicable 18
Ice Storm18 of 1811.132.851.7Relatively Low 9, Very Low 9
Inland Flooding18 of 188.459.978.3Relatively Moderate 14, Relatively Low 3, Very Low 1
Landslide17 of 1851.181.495.0Relatively Low 9, Very Low 8, No Rating 1
Lightning18 of 1855.887.597.2Very High 1, Relatively High 15, Relatively Moderate 2
Strong Wind18 of 1878.896.799.0Very High 9, Relatively High 8, Relatively Moderate 1
Tornado18 of 1862.688.898.3Very High 4, Relatively High 12, Relatively Moderate 2
Wildfire18 of 1833.070.083.4Relatively Low 10, Very Low 8
Winter Weather18 of 1848.175.387.8Relatively High 7, Relatively Moderate 10, Relatively Low 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
St. Croix CountyCountyApproved, expires 2029-02-25FMA RL 0, SRL 0; any 0$15,347.770 total; 0 since its plan
Baldwin villageVillageApproved, expires 2029-02-25FMA RL 0, SRL 0; any 1no Public Assistance recorded25 total; 7 since its plan
Deer Park villageVillageApproved, expires 2029-02-25FMA RL 0, SRL 0; any 0no Public Assistance recorded15 total; 0 since its plan
Glenwood City cityCityApproved, expires 2029-02-25FMA RL 0, SRL 0; any 0no Public Assistance recorded18 total; 0 since its plan
Hammond villageVillageApproved, expires 2029-02-25FMA RL 0, SRL 0; any 0no Public Assistance recorded28 total; 1 since its plan
Hudson cityCityApproved, expires 2029-02-25FMA RL 0, SRL 0; any 1$229,558.1550 total; 3 since its plan
New Richmond cityCityApproved, expires 2029-02-25FMA RL 0, SRL 0; any 1$13,788.8638 total; 7 since its plan
North Hudson villageVillageApproved, expires 2029-02-25FMA RL 0, SRL 0; any 0$61,268.429 total; 1 since its plan
River Falls cityCityPlan 110709 approved 2025-04-22, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 0no Public Assistance recorded34 total; no approved plan
Roberts villageVillageApproved, expires 2029-02-25FMA RL 0, SRL 0; any 0no Public Assistance recorded25 total; 0 since its plan
Somerset villageVillageApproved, expires 2029-02-25FMA RL 0, SRL 0; any 0$4,458.7528 total; 2 since its plan
Spring Valley villageVillagePlan 110709 approved 2025-04-22, pending adoption here; not yet eligibleFMA RL 0, SRL 0; any 0no Public Assistance recorded0 total; no approved plan
Star Prairie villageVillageApproved, expires 2029-02-25FMA RL 0, SRL 0; any 0no Public Assistance recorded21 total; 3 since its plan
Woodville villageVillageApproved, expires 2029-02-25FMA RL 0, SRL 0; any 0no Public Assistance recorded9 total; 1 since its plan

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

School districts and special districts get a plan clock row only.

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 2024-02-26county-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$24,884,276,568$243,465,92793,429$85$1,311$4,426,508under 0.0001%$0
Droughtn/a$25,505,209n/an/a$152n/a0.000596% (agriculture)NRI has no building exposure for this hazard; agriculture shown
Earthquake$40,998,701,269n/a93,536$8,348n/a$2,080under 0.0001%
Hail$24,884,276,568$243,465,92793,429$1,918,325$213,670$107,8780.00771%$0
Heat Wave$24,884,276,568$243,465,92793,429$1,032$2$538,908under 0.0001%
HurricaneNot Applicable in NRI for this county
Ice Storm$24,531,448,759n/a92,054$3,839n/a$58,261under 0.0001%
Inland Flooding$24,872,556,568$6,897,4671,513$15,361,646$36,538$342,063n/a (see note)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$486,085,095n/a1,830$1,019n/a$6,8430.00021%
Lightning$24,884,276,568n/a93,429$62,443n/a$880,7140.000251%
Strong Wind$24,884,276,568$243,465,92793,429$2,647,430$220,816$1,055,5230.0106%$0
Tornado$24,884,276,568$243,465,92793,429$3,854,680$5,047$4,045,2150.0155%$0
Wildfire$3,513,614,489$41,479,95320,387$47,185$39$5,9350.00134%
Winter Weather$24,884,276,568$243,465,92793,429$24,089$1,372$144,223under 0.0001%$0

Totals since 2024-02-26 (Storm Events through 2026-06-30): 32 county-coded records, 30 with a damage value recorded (including $0), $0; 20 zone-level records, 20 with a damage value recorded (including $0), $0 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
Population93,429
Building value (total, not at risk)$24,884,276,568
Agriculture value (total, not at risk)$243,465,927
NRI risk rating (all hazards)Relatively Low
Expected annual loss, buildings and agriculture, all hazards$24,409,067
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)$11,614,151
Social vulnerability ratingVery Low
Community resilience ratingRelatively 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 definition3Severe 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 total0030301
of which: Baldwin village0010101
of which: New Richmond city0010100
of which: Hudson city0010100
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 insuredproperties
St. Croix County5555780000000
Baldwin village5503800010101
Deer Park village5505620000000
Glenwood City city5503810000000
Hammond village5503820000000
Hudson city5555580010100
New Richmond city5503840010100
North Hudson village5555680000000
River Falls city5503300000000
Roberts village5500780000000
Somerset village5503860000000
Spring Valley village5503310000000
Star Prairie village5503870000000
Woodville village5503900000000

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 residential0020200
2 to 4 unit residential0000000
other residential0010101
non-residential0000000
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 3 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). St. Croix County, WI: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 55109). Automated baseline. https://hazardplain.org/wi/55109/ 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