Grafton County, New Hampshire
Natural disaster risk, federal disaster history and flood insurance facts.
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
- 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.
- 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.
- Insulate pipes in outside walls, crawl spaces and garages.
- Know how to shut off the main water valve.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Inland flooding | 90.1 | $43M | ||
| Hurricane | 78.5 | $2M | ||
| Cold wave | 54.1 | $1M | ||
| Earthquake | 69.6 | $848K | ||
| Lightning | 80.9 | $828K | ||
| Winter weather | 93.3 | $608K | ||
| Strong wind | 48.3 | $577K | ||
| Landslide | 97.8 | $544K | ||
| Tornado | 24.4 | $378K | ||
| Ice storm | 75.8 | $332K | ||
| Heat wave | 44.3 | $310K | ||
| Hail | 19.2 | $75K | ||
| Wildfire | 30.9 | $16K | ||
| Avalanche | 74.1 | $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
Most recent
Show all 38
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.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Aug 11, 1966 | F2 | – | 0 / 0 |
| May 11, 1973 | F2 | – | 0 / 0 |
| Jul 16, 2024 | EF1 | Hanover Center | 0 / 0 |
| Jul 21, 1972 | F1 | – | 0 / 0 |
| Jul 21, 1972 | F1 | – | 0 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| Jul 2, 2013 | Flash Flood | Lebanon | $7M |
| Jul 1, 2017 | Flash Flood | Hanover Center | $6M |
| Jul 1, 2017 | Flash Flood | Orford | $4M |
| Aug 28, 2011 | Flood | Lebanon Rgnl Ar | $3M |
| Aug 28, 2011 | Flood | Plymouth | $3M |
| Aug 28, 2011 | Flash Flood | Lincoln | $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.
Strongest storms nearby
| Date | Storm | Strength | Closest |
|---|---|---|---|
| Sep 9, 1869 | Unnamed | Category 1, 85 mph | 62 mi |
| Sep 27, 1985 | Gloria | Category 1, 75 mph | 57 mi |
| Sep 13, 1960 | Donna | Tropical storm, 70 mph | 62 mi |
| Sep 30, 1874 | Unnamed | Tropical storm, 70 mph | 62 mi |
| Sep 16, 1858 | Unnamed | Tropical storm, 70 mph | 53 mi |
| Aug 24, 1893 | Unnamed | Tropical storm, 70 mph | 55 mi |
Most recent storms
| Date | Storm | Strength | Closest |
|---|---|---|---|
| Sep 27, 1985 | Gloria | Category 1, 75 mph | 57 mi |
| Aug 28, 1971 | Doria | Tropical storm, 55 mph | 41 mi |
| Sep 13, 1960 | Donna | Tropical storm, 70 mph | 62 mi |
| Jul 31, 1960 | Brenda | Tropical storm, 45 mph | 46 mi |
| Oct 19, 1923 | Unnamed | Tropical storm, 50 mph | 60 mi |
| Aug 29, 1893 | Unnamed | Tropical storm, 60 mph | 57 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 ›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
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 counties | Overall risk | Top hazard |
|---|---|---|
| Hillsborough County | Inland flooding | |
| Rockingham County | Inland flooding | |
| Merrimack County | Inland flooding | |
| Strafford County | Inland flooding | |
| Grafton County | Inland flooding | |
| Cheshire County | Inland flooding | |
| Belknap County | Inland flooding | |
| Carroll County | Inland flooding |
Neighboring counties
| County | Overall risk | Declarations |
|---|---|---|
| Merrimack County | 27 | |
| Belknap County | 28 | |
| Windsor County, VT | 25 | |
| Carroll County | 34 | |
| Sullivan County | 31 | |
| Coos County | 26 | |
| Caledonia County, VT | 29 | |
| Orange County, VT | 32 |
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.