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Natural hazard risk in Lewis County, New York

Updated October 30, 2026. Based on FEMA, NOAA and OpenFEMA data. Published by Humblebee.

FEMA overall Risk Index rating: Very Low (score 24.7 of 100)[5]

Expected annual loss (FEMA)
$9.1 million[1]
Federal disaster declarations since 1977
24[2]
NFIP flood claims paid, 1978 to 2026
$456,000[3]
Tornadoes recorded, 1950 to 2024
8[4]

FEMA's National Risk Index rates overall natural hazard risk for Lewis County, New York as Very Low, with a score of 24.7 out of 100[5]. The hazards with the highest FEMA scores within the county are ice storm and winter weather, both rated Relatively Moderate[6].

FEMA risk ratings for each hazard

Ratings and expected losses from the FEMA National Risk Index. Each rating compares this county with all US counties for that hazard, from Very Low to Very High. They are planning estimates, not predictions, and they do not describe any single property.

FEMA estimates Expected Annual Loss from all 18 natural hazards in Lewis County at $9.1 million a year, and rates that Very Low compared with other US counties[1]. FEMA's sorted loss values show the largest are inland flooding at $7.3 million a year, then cold wave at $380,000 a year, then strong wind at $354,000 a year[7]. Expected Annual Loss is an estimate of average yearly loss, and FEMA says the index does not predict next year's damage[8]. FEMA rates Social Vulnerability Relatively Low[9]. This describes how susceptible social groups are to harm from natural hazards[9]. FEMA rates Community Resilience Very High, which describes a community's ability to prepare for, withstand and recover from hazards[10].

Hazards sorted by FEMA hazard-type Risk Index score, highest first
HazardFEMA risk ratingExpected annual loss
Ice StormRelatively Moderate$294,000[11]
Winter WeatherRelatively Moderate$136,000[12]
LandslideVery Low$1,848[13]
Inland FloodingRelatively Low$7.3 million[14]
HurricaneVery Low$64,000[15]
EarthquakeVery Low$255,000[16]
Strong WindRelatively Low$354,000[17]
Cold WaveRelatively Low$380,000[18]
LightningVery Low$89,000[19]
TornadoVery Low$201,000[20]
Heat WaveVery Low$41,000[21]
WildfireVery Low$4,951[22]
HailVery Low$22,000[23]

Rated Not Applicable by FEMA for this county: avalanche, coastal flooding, tsunami, volcanic activity[24].

Social vulnerability and community resilience

FEMA uses these two ratings to scale expected losses into the Risk Index.

FEMA measureRatingScore
Social vulnerabilityRelatively Low28.6[9]
Community resilienceVery High83.5[10]

Flooding and flood insurance

FEMA rates inland flooding risk Relatively Low compared with other US counties, with an Expected Annual Loss of $7.3 million a year[14]. OpenFEMA lists 59 residential flood insurance contracts in force out of 14,255 residential structures, as of 2026-08-03[25]. OpenFEMA NFIP claims data show 38 claims for losses from 1978 to 2026, and NFIP paid $456,000 in total[3]. Flood zones apply to specific properties, so check an address at FEMA's Flood Map Service Center[26].

Measure Value
Inland Flooding, FEMA risk rating[14] Relatively Low, $7.3 million expected loss a year
NFIP residential flood policies in force (2026)[25] 59 of 14,255 homes
NFIP flood claims, 1978 to 2026[3] 38 filed, $456,000 paid

Is a specific address in a flood zone? Only FEMA's flood maps answer that, property by property[26]. This page describes the whole county.

Search an address on the FEMA Flood Map Service Center

Disaster declarations and tornado records

OpenFEMA lists 24 federal disaster declarations for natural hazards that include Lewis County since 1977[2]. The most recent listed was DR-4839-NY, Severe Storm And Flooding, declared 2024-10-21[27]. NOAA's tornado database records 8 tornadoes touching the county from 1950 to 2024[4]. The most recent was on 2023-08-07[4].

Federal disaster declarations for natural hazards that include Lewis County, since 1977
Incident type Declarations
Snowstorm[2] 9
Severe Storm[2] 6
Flood[2] 4
Hurricane[2] 3
Winter Storm[2] 1
Fire[2] 1
Most recent declarations
Declaration Incident Declared
DR-4839-NY[27] Severe Storm And Flooding 2024-10-21
DR-4814-NY[27] Severe Storm, Tornadoes, And Flooding 2024-08-29
EM-3589-NY[27] Severe Winter Storm And Snowstorm 2022-11-20
DR-4625-NY[27] Remnants Of Tropical Storm Fred 2021-10-08
DR-4472-NY[27] Severe Storms, Straight-Line Winds, And Flooding 2019-12-19

How to prepare

Steps from Ready.gov, FEMA's preparedness site, for the hazards with the highest FEMA ratings here. Follow instructions from local officials and the National Weather Service when a warning is issued.

Winter storms and cold

Before

  • Insulate your home and learn how to keep pipes from freezing.
  • Install and test smoke and carbon monoxide detectors with battery backup.
  • Keep several days of supplies in case the power goes out, including medication and pet needs.
  • Put an emergency kit in your car with jumper cables, sand, blankets, water and snacks, and keep the tank full.

During

  • Under a winter storm warning, find shelter right away.
  • Stay off the roads if you can. If you are stuck in your car, stay inside it.
  • Run generators and grills only outdoors, away from windows, and never heat your home with an oven or stove.

Source: Ready.gov, winter storms and cold

Floods

Before

  • Check your flood risk with FEMA's Flood Map Service Center, and remember that floods do not follow map lines.
  • Sign up for your community's warning system. NOAA Weather Radio also broadcasts alerts.
  • Buy flood insurance through the NFIP well before a disaster. Homeowners policies do not cover flooding, and a new policy typically takes up to 30 days to go into effect.
  • Make a household plan with evacuation routes, shelter locations and what to do in a flash flood.
  • Keep important documents in a waterproof container and make password-protected digital copies.

During

  • If you are told to evacuate, leave right away and never drive around barricades.
  • Do not walk, swim or drive through floodwater. Six inches of moving water can knock you down.
  • If you are trapped in a building, go to the highest level, but do not climb into a closed attic.

Source: Ready.gov, floods

Questions people ask

Is Lewis County, NY at risk of flooding?
FEMA rates inland flooding risk Relatively Low compared with other US counties, but it drives the largest share of expected losses at $7.3 million a year[14][7]. For a specific address, use FEMA's Flood Map Service Center[26].
Does Lewis County, NY get tornadoes?
NOAA's tornado database records 8 tornadoes touching the county from 1950 to 2024[4]. FEMA rates tornado risk Very Low compared with other US counties[20].
Is Lewis County, NY at risk of earthquakes?
FEMA rates earthquake risk Very Low compared with other US counties[16].
How many disasters have been declared in Lewis County, NY?
OpenFEMA lists 24 federal disaster declarations for natural hazards that include the county since 1977[2].
Is Lewis County, NY at risk of wildfire?
FEMA rates wildfire risk Very Low compared with other US counties[22].

Facts and sources

  1. FEMA National Risk Index (version 1.20, December 2025): Expected Annual Loss from all 18 natural hazards in Lewis County is $9.1 million a year (Expected Annual Loss rating Very Low, score 31.4). Of this, buildings account for $8.1 million, injuries and deaths (converted to dollars by FEMA) for $937,000 and... FEMA National Risk Index
  2. OpenFEMA Disaster Declarations Summaries list 24 federal disaster declarations for natural hazards that include Lewis County since 1977 (16 major disaster, 8 emergency or fire management). By incident type: snowstorm 9, severe storm 6, flood 4, hurricane 3, winter storm 1, fire 1. Biological (such as COVID-19) and... OpenFEMA Disaster Declarations
  3. HazardFacts tally of OpenFEMA NFIP Redacted Claims (losses from 1978 to 2026): 38 National Flood Insurance Program claims were filed for losses in Lewis County, 31 of them with a payment, and NFIP paid $456,000 in total (building, contents and increased cost of compliance, in dollars of the year paid). Years with... OpenFEMA NFIP claims
  4. NOAA Storm Prediction Center tornado database (1950 to 2024): 8 recorded tornadoes touched Lewis County. The strongest were rated EF3 (most recent of them on 2023-08-07). 1 were rated F3/EF3 or stronger. The most recent recorded tornado was on 2023-08-07. Ratings used the Fujita scale until early 2007 and the... NOAA Storm Prediction Center
  5. FEMA National Risk Index (version 1.20, December 2025): the overall natural hazard Risk Index rating for Lewis County is Very Low, with a Risk Index score of 24.7 out of 100. The score is the county's percentile rank among all US counties. FEMA National Risk Index
  6. Among the 18 hazards in the FEMA National Risk Index (version 1.20, December 2025), the hazards with the highest hazard-type Risk Index scores for Lewis County are ice storm (73.6, Relatively Moderate), winter weather (69.0, Relatively Moderate), landslide (53.4, Very Low). HazardFacts sorted FEMA's published... FEMA National Risk Index
  7. HazardFacts sorted FEMA's hazard-type Expected Annual Loss values for Lewis County (National Risk Index v1.20): the largest are inland flooding ($7.3 million a year), cold wave ($380,000 a year), strong wind ($354,000 a year), out of $9.1 million a year from all 18 hazards. FEMA National Risk Index
  8. FEMA's National Risk Index FAQ (December 2025): Expected Annual Loss is FEMA's estimate of the average economic loss in dollars from natural hazards each year. The index is not meant to predict how much damage a community will have in the next year, and a hazard can still cause damage where a rating is low. Scores... FEMA National Risk Index documentation
  9. FEMA National Risk Index (version 1.20, December 2025): Social Vulnerability rating for Lewis County is Relatively Low (score 28.6). FEMA describes social vulnerability as how susceptible social groups are to the harm natural hazards cause. FEMA National Risk Index
  10. FEMA National Risk Index (version 1.20, December 2025): Community Resilience rating for Lewis County is Very High (score 83.5). FEMA describes community resilience as a community's ability to prepare for, withstand and recover from hazards. FEMA National Risk Index
  11. FEMA National Risk Index (version 1.20, December 2025), ice storm in Lewis County: Risk Index rating Relatively Moderate (score 73.6 of 100). Expected Annual Loss $294,000 a year (rating Relatively Moderate). Annualized frequency 0.73 event-days per year, from recorded occurrences over a period of record of 68 years. FEMA National Risk Index
  12. FEMA National Risk Index (version 1.20, December 2025), winter weather in Lewis County: Risk Index rating Relatively Moderate (score 69.0 of 100). Expected Annual Loss $136,000 a year (rating Relatively Moderate). Annualized frequency 42.14 events per year, from recorded occurrences over a period of record of 18... FEMA National Risk Index
  13. FEMA National Risk Index (version 1.20, December 2025), landslide in Lewis County: Risk Index rating Very Low (score 53.4 of 100). Expected Annual Loss $1,848 a year (rating Very Low). FEMA National Risk Index
  14. FEMA National Risk Index (version 1.20, December 2025), inland flooding in Lewis County: Risk Index rating Relatively Low (score 49.9 of 100). Expected Annual Loss $7.3 million a year (rating Relatively Low). Annualized frequency 1.04 event-days per year, from recorded occurrences over a period of record of 26 years. FEMA National Risk Index
  15. FEMA National Risk Index (version 1.20, December 2025), hurricane in Lewis County: Risk Index rating Very Low (score 47.3 of 100). Expected Annual Loss $64,000 a year (rating Very Low). Annualized frequency 0.01 events per year, from recorded occurrences over a period of record of 172 years for the Atlantic Basin... FEMA National Risk Index
  16. FEMA National Risk Index (version 1.20, December 2025), earthquake in Lewis County: Risk Index rating Very Low (score 46.8 of 100). Expected Annual Loss $255,000 a year (rating Very Low). FEMA's modeled annual frequency is 0.0017 events per year. FEMA National Risk Index
  17. FEMA National Risk Index (version 1.20, December 2025), strong wind in Lewis County: Risk Index rating Relatively Low (score 32.5 of 100). Expected Annual Loss $354,000 a year (rating Relatively Low). Annualized frequency 0.94 events per year, from recorded occurrences over a period of record of 38 years. FEMA National Risk Index
  18. FEMA National Risk Index (version 1.20, December 2025), cold wave in Lewis County: Risk Index rating Relatively Low (score 26.0 of 100). Expected Annual Loss $380,000 a year (rating Relatively Low). Annualized frequency 5.16 event-days per year, from recorded occurrences over a period of record of 18 years. FEMA National Risk Index
  19. FEMA National Risk Index (version 1.20, December 2025), lightning in Lewis County: Risk Index rating Very Low (score 23.6 of 100). Expected Annual Loss $89,000 a year (rating Relatively Low). Annualized frequency 25.77 events per year, from recorded occurrences over a period of record of 24 years. FEMA National Risk Index
  20. FEMA National Risk Index (version 1.20, December 2025), tornado in Lewis County: Risk Index rating Very Low (score 17.2 of 100). Expected Annual Loss $201,000 a year (rating Very Low). Annualized frequency 0.13 events per year, from recorded occurrences over a period of record of 38 years. FEMA National Risk Index
  21. FEMA National Risk Index (version 1.20, December 2025), heat wave in Lewis County: Risk Index rating Very Low (score 15.4 of 100). Expected Annual Loss $41,000 a year (rating Very Low). Annualized frequency 1.16 event-days per year, from recorded occurrences over a period of record of 18 years. FEMA National Risk Index
  22. FEMA National Risk Index (version 1.20, December 2025), wildfire in Lewis County: Risk Index rating Very Low (score 13.4 of 100). Expected Annual Loss $4,951 a year (rating Very Low). FEMA's modeled annual frequency is 0 events per year. FEMA National Risk Index
  23. FEMA National Risk Index (version 1.20, December 2025), hail in Lewis County: Risk Index rating Very Low (score 7.0 of 100). Expected Annual Loss $22,000 a year (rating Very Low). Annualized frequency 1.04 events per year, from recorded occurrences over a period of record of 37 years. FEMA National Risk Index
  24. FEMA National Risk Index (version 1.20, December 2025) rates these hazards Not Applicable for Lewis County: avalanche, coastal flooding, tsunami, volcanic activity. FEMA uses Not Applicable when its source data has no historical record of the hazard in the community and the hazard is not considered geographically... FEMA National Risk Index documentation
  25. NFIP Residential Penetration Rates (OpenFEMA, as of 2026-08-03): 59 residential flood insurance contracts were in force in Lewis County, out of 14,255 residential structures, a penetration rate of 0.4%. OpenFEMA NFIP penetration rates
  26. FEMA's Flood Map Service Center is the official public source for flood maps (Flood Insurance Rate Maps) produced under the National Flood Insurance Program. Flood zones apply to specific properties: look up an address there or ask the local floodplain manager. County-level ratings do not tell you the flood zone of... FEMA Flood Map Service Center
  27. Most recent federal disaster declarations for natural hazards (table on this page). OpenFEMA Disaster Declarations

FEMA's National Risk Index compares each county with all other US counties. Ratings are relative (Very Low to Very High), not a measure of safety. Never call a place safe, unsafe, good or bad to live in. Risk Index and Expected Annual Loss values are FEMA estimates for planning. They do not predict next year's losses and do not apply to a single property. Flood zones are set by FEMA flood maps for specific properties. County ratings and flood insurance counts do not tell anyone whether an address is in a flood zone. Disaster declaration, NFIP and tornado counts are records of the past for this county only. Do not compare with other counties unless a fact does.

Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties, v1.20 (December 2025). Retrieved from fema.maps.arcgis.com on October 30, 2026. This product uses the Federal Emergency Management Agency's National Risk Index dataset API or downloadable datasets but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s). This product uses the FEMA OpenFEMA API, but is not endorsed by FEMA.