FloodZoneMap.org

Grant County, Wisconsin Flood Zones

Check an Address in Grant County

Enter any address in Grant County, Wisconsin to see its FEMA flood zone

The Flooding Character of Grant County

Flash flooding from heavy rainfall events is the primary flood hazard in Grant County, WI. Over the past 30 years, NOAA Storm Events data shows 69 recorded flood events and 69 flash flood events. For example, on August 10th, 2025, two rounds of storms brought heavy rain and flash flooding, inundating residences in the town of Bagley due to a debris blockage. Later, on August 17th, 2025, heavy rainfall led to flash flooding in Lancaster.

National Flood Insurance Program (NFIP) claims data indicates that properties in Zone A and Zone X have experienced the most claims. While Zone A claims averaged a lower payout and water depth, Zone X claims, though fewer, had a higher average payout and water depth. Homeowners in areas designated as Zone A or Zone X, as well as those in areas with unknown flood risk, should pay particular attention to flood preparedness.

Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.

Read First-Hand Flood Stories from Grant County

77 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.

Read Wisconsin flood stories →

Flood Risk Data for Grant County

Grant County, Wisconsin has recorded 138 flood-related events since 1996 according to NOAA's Storm Events Database, including 69 flash floods and 69 river or area floods. The county has received 20 federal disaster declarations, 4 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.

Grant County Disaster History

FEMA Disaster Declarations (1965–2020)

Disaster Declarations
20
Flood/Coastal Disasters
4
Latest Disaster
Covid-19 (2020-01-20)

Source: OpenFEMA Disaster Declarations Summaries.

Recent Disaster Declarations in Grant County

DeclarationTypeDate
Covid-19BiologicalJan 20, 2020
Covid-19 PandemicBiologicalJan 20, 2020
Severe Storms, Straight-line Winds, Flooding, Landslides, And MudSevere StormJul 19, 2017
Severe Storms, Flooding, And MudslidesSevere StormJun 20, 2013
Severe Winter Storm And SnowstormSnowstormJan 31, 2011
Severe Storms, Tornadoes, And FloodingSevere StormJul 20, 2010
Severe Storms, Tornadoes, And FloodingSevere StormJun 5, 2008
Severe Storms And FloodingSevere StormAug 18, 2007
Hurricane Katrina EvacuationHurricaneAug 29, 2005
Severe Storms And FloodingSevere StormMay 7, 2004

Recorded Flood Events in Grant County

NOAA Storm Events Database (1996–2025)

Total Flood Events
138
River/Area Floods
69
Flash Floods
69
Total Property Damage
$46.1M

Source: NOAA National Weather Service Storm Events Database.

Recent Flood Events in Grant County

TypeDateDamage
FloodAug 18, 20250.00K
Flash FloodAug 17, 202575.00K
Flash FloodJul 11, 20250.00K
Flash FloodJul 11, 202525.00K
Flash FloodJul 11, 202510.00K
Flash FloodJul 11, 20255.00K
Flash FloodAug 10, 20255.00K
Flash FloodAug 10, 2025300.00K
Flash FloodAug 10, 202525.00K
Flash FloodJun 3, 20240.00K

Grant County Flood History

Flood — Aug 18, 2025

Heavy rainfall during the middle of August resulted in minor flooding along portions of the Trempealeau and Platte rivers in Western Wisconsin.

Flash Flood — Aug 17, 2025

Rounds of strong to severe storms throughout the day on August 16th resulted in instances of large hail, damaging winds and flash flooding in western Wisconsin. Hail with these storms reached up to golf ball sized near New Lisbon along with instances of tree damage. Later into the evening, additional storms moved through Grant County and produced heavy rainfall leading to flash flooding in Lanc...

Flash Flood — Jul 11, 2025

During the afternoon hours on July 11th, severe storms moved through Grant County bringing a few instances of severe wind gusts between 60 and 70 mph resulting in sporadic wind damage. These storms produced heavy rainfall as well which resulted in flash flooding of some county roads and some flooding of residences in Lancaster.

Flash Flood — Aug 10, 2025

Two separate rounds of storms moved through Grant County on August 10th bringing both heavy rain and flash flooding along with them. The first round of storms moved through during the early morning hours bringing widespread flooding issues to northern portions of the county. The worst of the flash flooding was in the town of Bagley where a debris blockage resulted in storm water inundating resi...

Flash Flood — Jun 3, 2024

During the late afternoon and evening hours on June 3rd, a cluster of thunderstorms produced heavy rainfall leading to mud slides and flooding on local roads and highways in Grant County.

Source: NOAA National Weather Service Storm Events Database.

Grant County NFIP Flood Insurance Claims

Total Claims Filed
76
Total Paid Out
$521,085
Avg Claim
$9,141
Avg Water Depth
2.4 ft

Claims by Flood Zone

A Zones (High Risk)
35
X Shaded (500-yr)
1
X Unshaded (Low)
14

Source: OpenFEMA NFIP Individual Claims (2.25M records analyzed).

Flood Zone Types in Grant County

FEMA assigns flood zone designations to areas in Grant County, Wisconsin:

AE High Risk — 1% annual chance of flooding. Insurance required.

VE Very High Risk — Coastal flooding with wave action.

X (Shaded) Moderate Risk — 500-year floodplain.

X Low Risk — Outside major floodplains.

View all flood zone types →

Flood Insurance in Grant County

Properties in Grant County, Wisconsin that are in FEMA-designated Special Flood Hazard Areas (zones A and V) with federally backed mortgages are required to carry flood insurance.

Even outside high-risk zones, flood insurance is recommended. From 2014 to 2024, nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area.

Visit FloodSmart.gov to find an agent and get a quote.