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Grafton County, New Hampshire Flood Zones

Check an Address in Grafton County

Enter any address in Grafton County, New Hampshire to see its FEMA flood zone

The Flooding Character of Grafton County

Flash flooding events are the most frequent type of flood recorded in Grafton County, NH over the last 30 years, with 107 such events documented. In addition to flash floods, 158 general flood events and 5 tropical storm events have occurred. For example, on July 10, 2024, heavy rainfall associated with the remnants of Tropical Storm Beryl led to significant runoff and flooding across northern New Hampshire.

National Flood Insurance Program (NFIP) data shows that properties in Zone A have experienced the highest number of claims, with 198 claims filed. These claims averaged a payout of $17,274 and an average water depth of 4.5 feet. Properties in Zone X also saw substantial claims, averaging $12,920 with 1.9 feet of water depth.

Homeowners in areas designated as Zone A, as well as those in Zone X, should pay particular attention to flood risk. Properties with a history of claims or those located in areas with documented water depth during flood events warrant careful consideration.

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

Read First-Hand Flood Stories from Grafton County

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

Read New Hampshire flood stories →

Flood Risk Data for Grafton County

Grafton County, New Hampshire has recorded 270 flood-related events since 1996 according to NOAA's Storm Events Database, including 107 flash floods and 158 river or area floods. The county has received 40 federal disaster declarations, 8 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.

Grafton County Disaster History

FEMA Disaster Declarations (1973–2024)

Disaster Declarations
40
Flood/Coastal Disasters
8
Hurricane Disasters
3
Latest Disaster
Severe Storm And Flooding (2024-07-10)

Source: OpenFEMA Disaster Declarations Summaries.

Recent Disaster Declarations in Grafton County

DeclarationTypeDate
Severe Storm And FloodingSevere StormJul 10, 2024
Severe Winter Storm And FloodingWinter StormApr 3, 2024
Severe Storms And FloodingSevere StormJan 9, 2024
Severe Storm And FloodingSevere StormDec 17, 2023
Severe Storms And FloodingFloodJul 9, 2023
Severe Storm And FloodingSevere StormDec 22, 2022
Covid-19BiologicalJan 20, 2020
Covid-19 PandemicBiologicalJan 20, 2020
Severe Storm And FloodingSevere StormJul 11, 2019
Severe Storm And FloodingSevere StormOct 29, 2017

Recorded Flood Events in Grafton County

NOAA Storm Events Database (1996–2025)

Total Flood Events
270
River/Area Floods
158
Flash Floods
107
Hurricanes/Tropical Storms
5
Total Property Damage
$45.6M
Flood Deaths
2
Flood Injuries
2

Source: NOAA National Weather Service Storm Events Database.

Recent Flood Events in Grafton County

TypeDateDamage
Flash FloodJul 31, 20240.00K
Flash FloodJul 30, 20240.00K
FloodApr 12, 20240.00K
Flash FloodJul 10, 20240.00K
Flash FloodJul 6, 20240.00K
Flash FloodJun 28, 20230.00K
Flash FloodJun 25, 20230.00K
Flash FloodJul 18, 20230.00K
Flash FloodDec 18, 20230.00K
FloodDec 18, 2023250.00K

Grafton County Flood History

Flash Flood — Jul 31, 2024

An area of low pressure supported widespread showers and thunderstorms on July 30th and 31st. Slow storm motions allowed heavy rain to fall over the same area, with high rainfall rates over 2 inches per hour. The most significant flooding occurred over Grafton County where saturated ground conditions and steep terrain supported flash flooding in Piermont.

Flash Flood — Jul 30, 2024

An area of low pressure supported widespread showers and thunderstorms on July 30th and 31st. Slow storm motions allowed heavy rain to fall over the same area, with high rainfall rates over 2 inches per hour. The most significant flooding occurred over Grafton County where saturated ground conditions and steep terrain supported flash flooding in Piermont.

Flood — Apr 12, 2024

A cold front brought widespread soaking rainfall to the area. This rainfall combined with significant snowpack loss and saturated grounds to produce minor to moderate river flooding, with isolated flash flooding across the mountains. Repeated rounds of rain compressed, warmed, and ripened the area snowpack in advance of the heavier rain on Friday the 12th. The combination of rain, strong winds,...

Flash Flood — Jul 10, 2024

On July 10th the remnants of Tropical Storm Beryl phased with a low pressure system out of the Great Lakes to bring multiple rounds of heavy rainfall to northern New England, including Maine and New Hampshire. The previous 3 days had brought a swath of heavy rain just north of the White Mountains, saturating the ground and making it ideal for runoff. During the roughly 36 hour period, 3 to as m...

Flash Flood — Jul 6, 2024

A slow moving cold front triggered scattered thunderstorms across northern New Hampshire on July 6th. Repeating storms across Grafton and Coos Counties produced locally heavy rainfall resulting in localized areas of road washouts.

Source: NOAA National Weather Service Storm Events Database.

Grafton County NFIP Flood Insurance Claims

Total Claims Filed
288
Total Paid Out
$4.2M
Avg Claim
$19,176
Avg Water Depth
6.3 ft

Claims by Flood Zone

A Zones (High Risk)
198
X Shaded (500-yr)
2
X Unshaded (Low)
22

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

Flood Zone Types in Grafton County

FEMA assigns flood zone designations to areas in Grafton County, New Hampshire:

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 Grafton County

Properties in Grafton County, New Hampshire 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.