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Grafton County, New Hampshire

Natural disaster risk, federal disaster history and flood insurance facts.

Relatively Moderate overall risk
3rd of 10highest risk in New Hampshire
$50Mexpected losses a year
38federal declarations
1 in 91homes with flood insurance
Photo: U.S. Geological Survey, public domain

Grafton County, New Hampshire has a moderate overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 82% of US counties. It ranks 3rd of 10 counties in New Hampshire. The costliest hazards here are inland flooding, hurricanes and cold waves. FEMA estimates about $50 million a year in expected losses, or roughly $554 per resident. Since 1973 it has been included in 38 federal disaster or emergency declarations for natural events (28 major disasters). The most recent was in August 2024 (severe storm and flooding). About 1 in 91 homes here carry federal flood insurance (330 policies). Since 1978, federal flood insurance has paid about $4.7 million on 363 claims here, including $2.3 million for floods in 2011.

FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.

Top risks in Grafton County

$43 million a yearExpected losses. Damaging events about 4 times a year.
  • Check the FEMA flood map for your address, and ask the seller or landlord about past flooding.
  • Price a flood policy now. Most new federal policies take 30 days to start.
$1.7 million a yearExpected losses. Damaging events about once every 15 years.
  • Know your evacuation zone and route before June 1.
  • Ask about roof age, shutters and the separate wind or hurricane deductible on your home policy.
$1.2 million a yearExpected losses. Damaging events about 4 times a year.
  • Insulate pipes in outside walls, crawl spaces and garages.
  • Know how to shut off the main water valve.
HazardRatingScoreExpected loss a year
Inland floodingModerate90.1
$43M
HurricaneLow78.5
$2M
Cold waveLow54.1
$1M
EarthquakeLow69.6
$848K
LightningModerate80.9
$828K
Winter weatherHigh93.3
$608K
Strong windLow48.3
$577K
LandslideModerate97.8
$544K
TornadoVery Low24.4
$378K
Ice stormModerate75.8
$332K
Heat waveLow44.3
$310K
HailVery Low19.2
$75K
WildfireVery Low30.9
$16K
AvalancheLow74.1
$13K

Scores are percentiles: a score of 90 means higher risk than about 90% of US counties for that hazard. Hazards FEMA does not rate here are left out. Social vulnerability is relatively low and community resilience is relatively high in FEMA's measures.

Federal disaster history

Recent disasters nationwide ›

Declarations by decade

Federal declarations for natural events that included Grafton County. 2020s bar runs to November 2026.

By type

Severe Storm17
Flood8
Hurricane6
Snowstorm5
Severe Ice Storm1
Winter Storm1

Most recent

Aug 20, 2024Severe Storm and FloodingMajor disaster
Jul 10, 2024Severe Winter Storm and FloodingMajor disaster
Apr 19, 2024Severe Storms and FloodingMajor disaster
Feb 27, 2024Severe Storm and FloodingMajor disaster
Sep 14, 2023Severe Storms and FloodingMajor disaster
Mar 15, 2023Severe Storm and FloodingMajor disaster
Aug 15, 2019Severe Storm and FloodingMajor disaster
Jan 2, 2018Severe Storm and FloodingMajor disaster
Aug 9, 2017Severe Storms and FloodingMajor disaster
Aug 2, 2013Severe Storms, Tornadoes, and FloodingMajor disaster
Show all 38
Nov 28, 2012Hurricane SandyMajor disaster
Oct 30, 2012Hurricane SandyEmergency
Nov 1, 2011Severe StormEmergency
Sep 3, 2011Tropical Storm IreneMajor disaster
Aug 27, 2011Hurricane IreneEmergency
Jul 22, 2011Severe Storms and FloodingMajor disaster
Mar 29, 2010Severe Winter StormMajor disaster
Jan 2, 2009Severe Winter StormMajor disaster
Dec 13, 2008Severe Winter StormEmergency
Sep 5, 2008Severe Storms and FloodingMajor disaster
Apr 27, 2007Severe Storms and FloodingMajor disaster
May 25, 2006Severe Storms and FloodingMajor disaster
Oct 26, 2005Severe Storms and FloodingMajor disaster
Sep 19, 2005Hurricane Katrina EvacuationEmergency
Mar 30, 2005Record And/Or Near Record SnowEmergency
Mar 30, 2005Record SnowEmergency
Jan 15, 2004SnowEmergency
Mar 28, 2001SnowEmergency
Oct 18, 1999Tropical Storm FloydMajor disaster
Jul 2, 1998Severe Storms and FloodingMajor disaster
Jan 15, 1998Severe Ice Storm, Rains and High WindsMajor disaster
Oct 29, 1996Fall Northeaster RainstormMajor disaster
Jan 3, 1996Excessive Rainfall, High Winds, and FloodingMajor disaster
Mar 16, 1993Blizzards, High Winds & Record SnowfallEmergency
Aug 29, 1990Severe Storms & FloodingMajor disaster
Apr 16, 1987Severe Storms & FloodingMajor disaster
Jan 21, 1974Heavy Rains & FloodingMajor disaster
Jul 11, 1973Severe Storms & FloodingMajor disaster

New Hampshire also had 1 statewide declarations that did not name single counties.

Storm history since 1957

Tornado risk by county ›

The National Weather Service has logged 792 storm reports in Grafton County since 1957, with 3 deaths and 11 injuries and about $46.4 million in reported damage. The strongest on record here was an F2 tornado on August 11, 1966.

14tornadoes
135hail reports, largest 3 inches
413damaging thunderstorm winds
218floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
Aug 11, 1966F2–0 / 0
May 11, 1973F2–0 / 0
Jul 16, 2024EF1Hanover Center0 / 0
Jul 21, 1972F1–0 / 0
Jul 21, 1972F1–0 / 0

Most damaging storms

DateTypeNearDamage
Jul 2, 2013Flash FloodLebanon$7M
Jul 1, 2017Flash FloodHanover Center$6M
Jul 1, 2017Flash FloodOrford$4M
Aug 28, 2011FloodLebanon Rgnl Ar$3M
Aug 28, 2011FloodPlymouth$3M
Aug 28, 2011Flash FloodLincoln$3M

Source: NOAA Storm Events Database, county-based reports through Jul 14, 2026. Tornado records start in 1950, hail and wind in 1955, and floods and other storm types in 1996, so older decades undercount. Damage is in dollars of the year it happened and is often an estimate. Winter storms, heat and hurricanes are logged by forecast zone, not county, so they are not counted here.

Hurricanes and tropical storms

Hurricane risk by county ›

Since 1858, 2 hurricanes and 8 tropical storms have passed within 65 miles of the center of Grafton County, 4 of them since 1950. The strongest was an unnamed hurricane in 1869, with top winds near 85 mph about 62 miles away.

2hurricanes
0major hurricanes (Category 3+)
8tropical storms
1985most recent: Gloria

Strongest storms nearby

DateStormStrengthClosest
Sep 9, 1869UnnamedCategory 1, 85 mph62 mi
Sep 27, 1985GloriaCategory 1, 75 mph57 mi
Sep 13, 1960DonnaTropical storm, 70 mph62 mi
Sep 30, 1874UnnamedTropical storm, 70 mph62 mi
Sep 16, 1858UnnamedTropical storm, 70 mph53 mi
Aug 24, 1893UnnamedTropical storm, 70 mph55 mi

Most recent storms

DateStormStrengthClosest
Sep 27, 1985GloriaCategory 1, 75 mph57 mi
Aug 28, 1971DoriaTropical storm, 55 mph41 mi
Sep 13, 1960DonnaTropical storm, 70 mph62 mi
Jul 31, 1960BrendaTropical storm, 45 mph46 mi
Oct 19, 1923UnnamedTropical storm, 50 mph60 mi
Aug 29, 1893UnnamedTropical storm, 60 mph57 mi

Source: NOAA National Hurricane Center best-track records (HURDAT2), 1851 to 2025 for the Atlantic and 1949 to 2025 for the eastern Pacific. A storm counts if its track passed within 65 miles of the county's center while it was a tropical storm or hurricane. Strength is the storm's top sustained wind at that point, not the wind measured in the county. Older storms over the open sea were sometimes missed.

Flood insurance in Grafton County

Check your address flood zone ›
1.1%of homes have federal flood insurance (330 policies)
18%of homes in mapped high-risk flood zones are insured
$4.7 millionpaid on 363 flood claims since 1978
2011costliest year, with $2.3 million paid

National Flood Insurance Program (NFIP) records only; private flood policies are not included. Home counts as of Aug 3, 2026. Since 2021 NFIP prices each home separately under Risk Rating 2.0, so your price depends on the building, not the county. Ask an agent for a quote.

Homes in Grafton County

$344,500median home value (New Hampshire $402,500, US $332,700)
1981median year homes were built (New Hampshire 1979, US 1980)
48%of homes built before 1980, before many modern wind, quake and flood building rules
7.2%of homes are mobile homes, which are the least safe in tornadoes and high winds

Older homes and mobile homes usually suffer more damage in storms, floods and earthquakes, and can cost more to insure. If you are buying, ask about roof age, foundation bolting and any retrofits. Source: US Census Bureau, American Community Survey 2020 to 2024 5-year estimates; 51,920 housing units.

Compare in New Hampshire

All 10 ›
Largest countiesOverall riskTop hazard
Hillsborough CountyModerateInland flooding
Rockingham CountyModerateInland flooding
Merrimack CountyLowInland flooding
Strafford CountyLowInland flooding
Grafton CountyModerateInland flooding
Cheshire CountyLowInland flooding
Belknap CountyLowInland flooding
Carroll CountyLowInland flooding

Neighboring counties

CountyOverall riskDeclarations
Merrimack CountyLow27
Belknap CountyLow28
Windsor County, VTLow25
Carroll CountyLow34
Sullivan CountyVery Low31
Coos CountyLow26
Caledonia County, VTVery Low29
Orange County, VTVery Low32

Common questions about Grafton County

What is the biggest natural hazard in Grafton County?

Inland flooding has the highest expected yearly losses in Grafton County, about $43 million a year in FEMA's estimate. Hurricane is second at $1.7 million.

How many federal disasters has Grafton County had?

Grafton County has been included in 38 federal disaster or emergency declarations for natural events since 1973, including 28 major disasters. The most recent was Severe Storm and Flooding in August 2024.

Is Grafton County a high-risk place to live?

Its overall rating is Relatively Moderate, 3rd highest of 10 in New Hampshire. A county rating covers the whole area. Risk at one address can be much higher or lower, so check the FEMA flood map and ask about the home's history.

Do I need flood insurance in Grafton County?

Standard home insurance does not cover flooding. About 1 in 91 homes in Grafton County has federal flood insurance. Lenders require it in mapped high-risk zones, but many flood claims come from outside those zones.

How many tornadoes has Grafton County had?

NOAA records list 14 tornadoes in Grafton County since 1950. The strongest was an F2 tornado on August 11, 1966. The weather service has also logged 135 hail reports and 218 floods here.

How many hurricanes have hit Grafton County?

NOAA's hurricane records show 2 hurricanes and 8 tropical storms passing within 65 miles of the center of Grafton County. The strongest was an unnamed hurricane in 1869, with winds near 85 mph.

Sources: FEMA National Risk Index (December 2025), OpenFEMA Disaster Declarations Summaries, and NFIP policy and claims data. Hazard Compass is independent and not affiliated with FEMA. These figures describe the whole county, not a single property, and are not insurance or safety advice. Report a problem.