Merrimack County, New Hampshire
Natural disaster risk, federal disaster history and flood insurance facts.
Merrimack County, New Hampshire has a relatively low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 78% of US counties. It ranks 4th of 10 counties in New Hampshire. The costliest hazards here are inland flooding, hurricanes and tornadoes. FEMA estimates about $49 million a year in expected losses, or roughly $317 per resident. Since 1973 it has been included in 27 federal disaster or emergency declarations for natural events (17 major disasters). The most recent was in January 2018 (severe storm and flooding). Fewer than 1 in 100 homes here carry federal flood insurance (333 policies). Since 1978, federal flood insurance has paid about $6.3 million on 299 claims here, including $2.4 million for floods in 2007.
FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.
Top risks in Merrimack 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.
- Pick a shelter spot: a basement, or an inside room on the lowest floor with no windows.
- Turn on emergency alerts on your phone and keep a weather radio.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Inland flooding | 85.8 | $34M | ||
| Hurricane | 84.8 | $4M | ||
| Tornado | 56.2 | $2M | ||
| Earthquake | 76.1 | $2M | ||
| Lightning | 89.2 | $1M | ||
| Cold wave | 53.8 | $1M | ||
| Heat wave | 70.6 | $1M | ||
| Ice storm | 89.8 | $1M | ||
| Strong wind | 52.5 | $748K | ||
| Drought | 58.8 | $329K | ||
| Winter weather | 80.4 | $268K | ||
| Hail | 37.2 | $202K | ||
| Wildfire | 35.2 | $24K | ||
| Landslide | 81.1 | $23K | ||
| Avalanche | 28.5 | $119 |
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 very low and community resilience is very high in FEMA's measures.
Federal disaster history
Recent disasters nationwide ›Declarations by decade
Federal declarations for natural events that included Merrimack County. 2020s bar runs to November 2026.
By type
Most recent
Show all 27
New Hampshire also had 1 statewide declarations that did not name single counties.
Storm history since 1962
Tornado risk by county ›The National Weather Service has logged 474 storm reports in Merrimack County since 1962, with 1 death and 15 injuries and about $12.1 million in reported damage. The strongest on record here was an EF2 tornado on July 24, 2008 near Epsom.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Jul 24, 2008 | EF2 | Epsom | 0 / 0 |
| Jul 12, 1967 | F1 | – | 5 / 0 |
| May 31, 1972 | F1 | – | 0 / 0 |
| Aug 15, 1976 | F1 | – | 5 / 0 |
| Jul 6, 1999 | F1 | Pittsfield | 0 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| Jul 9, 1997 | Lightning | Bradford | $3M |
| Oct 20, 1996 | Flash Flood | Countywide | $2M |
| Feb 25, 2010 | Flood | South Hooksett | $2M |
| Apr 16, 2007 | Flood | Concord | $1M |
| Aug 28, 2011 | Flood | Martin | $900K |
| May 13, 2006 | Flood | Countywide | $750K |
Source: NOAA Storm Events Database, county-based reports through Jul 16, 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 17 tropical storms have passed within 65 miles of the center of Merrimack County, 8 of them since 1950. The strongest was an unnamed hurricane in 1869, with top winds near 95 mph about 56 miles away.
Strongest storms nearby
| Date | Storm | Strength | Closest |
|---|---|---|---|
| Sep 8, 1869 | Unnamed | Category 2, 95 mph | 56 mi |
| Sep 27, 1985 | Gloria | Category 1, 80 mph | 64 mi |
| Sep 12, 1960 | Donna | Tropical storm, 70 mph | 54 mi |
| Sep 16, 1858 | Unnamed | Tropical storm, 70 mph | 41 mi |
| Sep 30, 1874 | Unnamed | Tropical storm, 70 mph | 63 mi |
| Jul 14, 1996 | Bertha | Tropical storm, 70 mph | 61 mi |
Most recent storms
| Date | Storm | Strength | Closest |
|---|---|---|---|
| Aug 28, 2011 | Irene | Tropical storm, 55 mph | 57 mi |
| Sep 17, 1999 | Floyd | Tropical storm, 55 mph | 55 mi |
| Jul 14, 1996 | Bertha | Tropical storm, 70 mph | 61 mi |
| Sep 27, 1985 | Gloria | Category 1, 80 mph | 64 mi |
| Aug 10, 1976 | Belle | Tropical storm, 40 mph | 61 mi |
| Aug 28, 1971 | Doria | Tropical storm, 55 mph | 46 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 Merrimack 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 Merrimack 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; 66,497 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 |
|---|---|---|
| Hillsborough County | 29 | |
| Rockingham County | 33 | |
| Strafford County | 23 | |
| Grafton County | 38 | |
| Belknap County | 28 | |
| Sullivan County | 31 |
Cities in Merrimack County
Common questions about Merrimack County
What is the biggest natural hazard in Merrimack County?
Inland flooding has the highest expected yearly losses in Merrimack County, about $34.1 million a year in FEMA's estimate. Hurricane is second at $4.5 million.
How many federal disasters has Merrimack County had?
Merrimack County has been included in 27 federal disaster or emergency declarations for natural events since 1973, including 17 major disasters. The most recent was Severe Storm and Flooding in January 2018.
Is Merrimack County a high-risk place to live?
Its overall rating is Relatively Low, 4th 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 Merrimack County?
Standard home insurance does not cover flooding. About 1 in 125 homes in Merrimack 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 Merrimack County had?
NOAA records list 7 tornadoes in Merrimack County since 1950. The strongest was an EF2 tornado on July 24, 2008 near Epsom. The weather service has also logged 102 hail reports and 102 floods here.
How many hurricanes have hit Merrimack County?
NOAA's hurricane records show 2 hurricanes and 17 tropical storms passing within 65 miles of the center of Merrimack County. The strongest was an unnamed hurricane in 1869, with winds near 95 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.