riskbycounty
FEMA National Risk Index

Merrimack County Disaster Risk

Merrimack County, New Hampshire

FEMA Risk Rating

Relatively Low

National Percentile

78th

of 3,144 counties

State Rank

#4

of 10 (1 = highest risk)

Flood Risk

86th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Moderate

Higher than 86% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Very Low

Higher than 35% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively Low

Higher than 56% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively Low

Higher than 76% of US counties

Hurricane

Tropical cyclone and hurricane risk

Moderate

Higher than 85% of US counties

Risk Advisory: Merrimack County

Risk Verdict

Merrimack County shows a relatively low overall disaster risk profile, scoring in the 78th percentile nationally. The county faces moderate hazard exposure relative to other U.S. counties. Standard emergency preparedness is recommended, with attention to the specific hazards that dominate locally.

Hazard Breakdown

Flood risk is the dominant hazard for Merrimack County, scoring in the 86th percentile nationally. It is followed by hurricane risk at the 85th percentile. Additional hazards include earthquake (76th), tornado (56th), wildfire (35th).

Preparedness Context

With flood risk as the top concern, Merrimack County residents should review flood insurance needs (standard home insurance does not cover flood damage), know your evacuation zone, and keep important documents waterproofed. Secondary risks such as hurricane also warrant attention in household and community preparedness planning. FEMA recommends all households maintain at least 72 hours of food, water, and medication supplies regardless of specific hazard exposure.

Regional Context

Merrimack County is significantly riskier than the average county in New Hampshire. Its composite risk score is 8.3 points higher than the state average, meaning residents face above-average exposure to natural hazards compared to their neighbors.

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Frequently Asked Questions

What is the natural disaster risk in Merrimack County, NH?
Merrimack County has a FEMA National Risk Index rating of Relatively Low, placing it in the 78th percentile nationally out of 3,144 counties. This composite score reflects the county's overall exposure to natural hazards including floods, wildfires, tornadoes, earthquakes, and hurricanes, weighted by expected annual loss and social vulnerability.
What types of natural hazards affect Merrimack County?
Merrimack County is evaluated for five major natural hazard types: flooding (86th percentile), hurricane (85th percentile), earthquake (76th percentile), tornado (56th percentile), wildfire (35th percentile). The highest-risk hazard is flooding at the 86th percentile nationally. These scores are derived from FEMA's National Risk Index, which analyzes expected annual loss, social vulnerability, and community resilience for each hazard type.
How does Merrimack County risk compare to the New Hampshire average?
Merrimack County's composite risk percentile is 78th, compared to the New Hampshire state average of 70th percentile. The state's overall risk rating is Relatively Low. This means Merrimack County faces higher natural disaster risk than the typical county in New Hampshire.
Is Merrimack County at risk for flooding?
Yes, Merrimack County's flooding risk is at the 86th percentile nationally. This places it in the top quartile for this hazard type.
How is natural disaster risk measured?
FEMA's National Risk Index (NRI) calculates risk scores for 18 natural hazard types across all U.S. counties and census tracts. The composite score combines Expected Annual Loss (estimated dollar losses from each hazard), Social Vulnerability (demographic factors affecting disaster impact), and Community Resilience (ability to recover). Percentile scores rank each county against all 3,144 U.S. counties, and risk ratings range from Very Low to Very High.
Why is Merrimack County higher risk than average?
Merrimack County's composite risk score of 78th percentile is above the New Hampshire state average of 70th percentile. This elevated risk is driven by flooding exposure (86th percentile), along with hurricane and earthquake and tornado risk. Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.

Counties with Similar Risk

Grafton County

New Hampshire

+3.6

Relatively Moderate

82th percentile

Coos County

New Hampshire

-5.4

Relatively Low

73th percentile

Carroll County

New Hampshire

-7.3

Relatively Low

71th percentile

By Logan Johnson, Founder & Data EditorUpdated Reviewed by Logan Johnson, Founder & Data Editor

Data Source

Risk data sourced from the FEMA National Risk Index (NRI). Risk scores are relative rankings (0–100) across all US counties — not absolute risk measures. Higher scores indicate higher relative risk compared to other counties.

Disclaimer: This data is informational only. It is not financial, insurance, or legal advice. Always consult a qualified professional before making insurance or real estate decisions.

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