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St. Lawrence County, New York

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

Relatively Low overall risk
25th of 62highest risk in New York
$32Mexpected losses a year
15federal declarations
1 in 500homes with flood insurance
Photo: U.S. Geological Survey, public domain

St. Lawrence County, New York 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 25th of 62 counties in New York. The costliest hazards here are inland flooding, cold waves and earthquakes. FEMA estimates about $32 million a year in expected losses, or roughly $295 per resident. Since 1991 it has been included in 15 federal disaster or emergency declarations for natural events (10 major disasters). The most recent was in September 2024 (remnants of tropical storm debby). Fewer than 1 in 100 homes here carry federal flood insurance (109 policies). Since 1978, federal flood insurance has paid about $1.7 million on 95 claims here, including $1.1 million for floods in 2024.

FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.

Top risks in St. Lawrence County

$21.7 million a yearExpected losses. Damaging events about once 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.

Cold wave

Moderate
$5.2 million a yearExpected losses. Damaging events about 5 times a year.
  • Insulate pipes in outside walls, crawl spaces and garages.
  • Know how to shut off the main water valve.
$2.7 million a yearExpected losses. Damaging events about once every 270 years.
  • Ask whether an older house is bolted to its foundation.
  • Consider separate earthquake insurance where risk is high.
HazardRatingScoreExpected loss a year
Inland floodingModerate85.0
$22M
Cold waveModerate88.6
$5M
EarthquakeLow86.5
$3M
Ice stormHigh87.3
$606K
LightningModerate77.6
$547K
Strong windLow35.2
$294K
TornadoVery Low24.2
$285K
Winter weatherHigh87.2
$274K
Heat waveVery Low37.4
$169K
HurricaneLow59.2
$158K
WildfireVery Low33.1
$15K
LandslideLow77.1
$10K
HailVery Low3.6
$6K
AvalancheVery Low17.8
$22

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 high 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 St. Lawrence County. 2020s bar runs to November 2026.

By type

Snowstorm6
Flood3
Hurricane2
Fire1
Severe Storm1
Winter Storm1

Most recent

Sep 24, 2024Remnants of Tropical Storm DebbyMajor disaster
Aug 29, 2024Severe Storm, Tornadoes, and FloodingMajor disaster
Mar 15, 2023Severe Winter Storm and SnowstormMajor disaster
Nov 20, 2022Severe Winter Storm and SnowstormEmergency
Nov 14, 2017FloodingMajor disaster
Dec 22, 2014Severe Winter Storm, Snowstorm, and FloodingMajor disaster
Oct 28, 2012Hurricane SandyEmergency
Sep 30, 2005Hurricane Katrina EvacuationEmergency
Aug 3, 2004Severe Storms and FloodingMajor disaster
Sep 11, 2001Fires and ExplosionsMajor disaster
Show all 15
Jan 15, 1999SnowEmergency
Jan 6, 1998Severe Storms and FloodingMajor disaster
Jan 24, 1996Severe Storms and FloodingMajor disaster
Mar 17, 1993Severe BlizzardEmergency
Mar 21, 1991Severe Winter StormMajor disaster

New York also had 12 statewide declarations that did not name single counties.

Storm history since 1954

Tornado risk by county ›

The National Weather Service has logged 479 storm reports in St. Lawrence County since 1954, with 1 death and 13 injuries and about $54.1 million in reported damage. The strongest on record here was an F2 tornado on August 15, 1986.

11tornadoes
76hail reports, largest 2.75 inches
349damaging thunderstorm winds
25floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
Aug 15, 1986F2–3 / 1
Sep 19, 1954F2–0 / 0
May 31, 1985F1–0 / 0
Aug 7, 1972F1–0 / 0
Jul 10, 1989F1–1 / 0

Most damaging storms

DateTypeNearDamage
Jul 15, 1995Thunderstorm WindCountywide$34M
Apr 15, 2014FloodNorth Corners$4M
Aug 9, 2024Flash FloodRensselaer Falls$3M
Aug 9, 2024FloodNelson Corners$2M
Aug 9, 2024Flash FloodWegatchie$2M
Apr 28, 2011FloodPlumbrook$1M

Source: NOAA Storm Events Database, county-based reports through Jul 15, 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.

Flood insurance in St. Lawrence County

Check your address flood zone ›
0.2%of homes have federal flood insurance (109 policies)
0%of homes in mapped high-risk flood zones are insured
$1.7 millionpaid on 95 flood claims since 1978
2024costliest year, with $1.1 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 St. Lawrence County

$121,900median home value (New York $423,800, US $332,700)
1964median year homes were built (New York 1959, US 1980)
67%of homes built before 1980, before many modern wind, quake and flood building rules
10%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; 51,970 housing units.

Compare in New York

All 62 ›
Largest countiesOverall riskTop hazard
Kings CountyHighInland flooding
Queens CountyHighInland flooding
New York CountyHighInland flooding
Suffolk CountyHighInland flooding
Bronx CountyHighInland flooding
Nassau CountyHighInland flooding
Westchester CountyHighInland flooding
Erie CountyHighInland flooding

Neighboring counties

CountyOverall riskDeclarations
Jefferson CountyLow17
Herkimer CountyLow21
Franklin CountyLow16
Lewis CountyVery Low24
Hamilton CountyVery Low14

Common questions about St. Lawrence County

What is the biggest natural hazard in St. Lawrence County?

Inland flooding has the highest expected yearly losses in St. Lawrence County, about $21.7 million a year in FEMA's estimate. Cold wave is second at $5.2 million.

How many federal disasters has St. Lawrence County had?

St. Lawrence County has been included in 15 federal disaster or emergency declarations for natural events since 1991, including 10 major disasters. The most recent was Remnants of Tropical Storm Debby in September 2024.

Is St. Lawrence County a high-risk place to live?

Its overall rating is Relatively Low, 25th highest of 62 in New York. 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 St. Lawrence County?

Standard home insurance does not cover flooding. About 1 in 500 homes in St. Lawrence 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 St. Lawrence County had?

NOAA records list 11 tornadoes in St. Lawrence County since 1950. The strongest was an F2 tornado on August 15, 1986. The weather service has also logged 76 hail reports and 25 floods here.

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.