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Merrimack County, New Hampshire

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

Relatively Low overall risk
4th of 10highest risk in New Hampshire
$49Mexpected losses a year
27federal declarations
1 in 125homes with flood insurance
Photo: U.S. Geological Survey, public domain

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

$34.1 million a yearExpected losses. Damaging events about 3 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.

Hurricane

Moderate
$4.5 million a yearExpected losses. Damaging events about once every 10 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.
$1.9 million a yearExpected losses. Damaging events about once every 8 years.
  • 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.
HazardRatingScoreExpected loss a year
Inland floodingModerate85.8
$34M
HurricaneModerate84.8
$4M
TornadoLow56.2
$2M
EarthquakeLow76.1
$2M
LightningHigh89.2
$1M
Cold waveLow53.8
$1M
Heat waveLow70.6
$1M
Ice stormHigh89.8
$1M
Strong windModerate52.5
$748K
DroughtLow58.8
$329K
Winter weatherModerate80.4
$268K
HailLow37.2
$202K
WildfireVery Low35.2
$24K
LandslideLow81.1
$23K
AvalancheVery Low28.5
$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

Severe Storm12
Flood5
Snowstorm5
Hurricane4
Severe Ice Storm1

Most recent

Jan 2, 2018Severe Storm and FloodingMajor disaster
Mar 19, 2013Severe Winter Storm and SnowstormMajor disaster
Oct 30, 2012Hurricane SandyEmergency
Nov 1, 2011Severe StormEmergency
Sep 3, 2011Tropical Storm IreneMajor disaster
Aug 27, 2011Hurricane IreneEmergency
Mar 29, 2010Severe Winter StormMajor disaster
Jan 2, 2009Severe Winter StormMajor disaster
Dec 13, 2008Severe Winter StormEmergency
Oct 3, 2008Severe Storms and FloodingMajor disaster
Show all 27
Aug 11, 2008Severe Storms, Tornado, 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
Jan 15, 2004SnowEmergency
Mar 11, 2003SnowEmergency
Mar 28, 2001SnowEmergency
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
Jul 11, 1973Severe Storms & FloodingMajor disaster

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.

7tornadoes
102hail reports, largest 2 inches
243damaging thunderstorm winds
102floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
Jul 24, 2008EF2Epsom0 / 0
Jul 12, 1967F1–5 / 0
May 31, 1972F1–0 / 0
Aug 15, 1976F1–5 / 0
Jul 6, 1999F1Pittsfield0 / 0

Most damaging storms

DateTypeNearDamage
Jul 9, 1997LightningBradford$3M
Oct 20, 1996Flash FloodCountywide$2M
Feb 25, 2010FloodSouth Hooksett$2M
Apr 16, 2007FloodConcord$1M
Aug 28, 2011FloodMartin$900K
May 13, 2006FloodCountywide$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.

2hurricanes
0major hurricanes (Category 3+)
17tropical storms
2011most recent: Irene

Strongest storms nearby

DateStormStrengthClosest
Sep 8, 1869UnnamedCategory 2, 95 mph56 mi
Sep 27, 1985GloriaCategory 1, 80 mph64 mi
Sep 12, 1960DonnaTropical storm, 70 mph54 mi
Sep 16, 1858UnnamedTropical storm, 70 mph41 mi
Sep 30, 1874UnnamedTropical storm, 70 mph63 mi
Jul 14, 1996BerthaTropical storm, 70 mph61 mi

Most recent storms

DateStormStrengthClosest
Aug 28, 2011IreneTropical storm, 55 mph57 mi
Sep 17, 1999FloydTropical storm, 55 mph55 mi
Jul 14, 1996BerthaTropical storm, 70 mph61 mi
Sep 27, 1985GloriaCategory 1, 80 mph64 mi
Aug 10, 1976BelleTropical storm, 40 mph61 mi
Aug 28, 1971DoriaTropical storm, 55 mph46 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 ›
0.8%of homes have federal flood insurance (333 policies)
20.1%of homes in mapped high-risk flood zones are insured
$6.3 millionpaid on 299 flood claims since 1978
2007costliest year, with $2.4 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 Merrimack County

$367,600median home value (New Hampshire $402,500, US $332,700)
1977median year homes were built (New Hampshire 1979, US 1980)
54%of homes built before 1980, before many modern wind, quake and flood building rules
6.8%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; 66,497 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
Hillsborough CountyModerate29
Rockingham CountyModerate33
Strafford CountyLow23
Grafton CountyModerate38
Belknap CountyLow28
Sullivan CountyVery Low31

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.