St. Lawrence County, New York
Natural disaster risk, federal disaster history and flood insurance facts.
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
- 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.
- Insulate pipes in outside walls, crawl spaces and garages.
- Know how to shut off the main water valve.
- Ask whether an older house is bolted to its foundation.
- Consider separate earthquake insurance where risk is high.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Inland flooding | 85.0 | $22M | ||
| Cold wave | 88.6 | $5M | ||
| Earthquake | 86.5 | $3M | ||
| Ice storm | 87.3 | $606K | ||
| Lightning | 77.6 | $547K | ||
| Strong wind | 35.2 | $294K | ||
| Tornado | 24.2 | $285K | ||
| Winter weather | 87.2 | $274K | ||
| Heat wave | 37.4 | $169K | ||
| Hurricane | 59.2 | $158K | ||
| Wildfire | 33.1 | $15K | ||
| Landslide | 77.1 | $10K | ||
| Hail | 3.6 | $6K | ||
| Avalanche | 17.8 | $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
Most recent
Show all 15
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.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Aug 15, 1986 | F2 | – | 3 / 1 |
| Sep 19, 1954 | F2 | – | 0 / 0 |
| May 31, 1985 | F1 | – | 0 / 0 |
| Aug 7, 1972 | F1 | – | 0 / 0 |
| Jul 10, 1989 | F1 | – | 1 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| Jul 15, 1995 | Thunderstorm Wind | Countywide | $34M |
| Apr 15, 2014 | Flood | North Corners | $4M |
| Aug 9, 2024 | Flash Flood | Rensselaer Falls | $3M |
| Aug 9, 2024 | Flood | Nelson Corners | $2M |
| Aug 9, 2024 | Flash Flood | Wegatchie | $2M |
| Apr 28, 2011 | Flood | Plumbrook | $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 ›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
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 counties | Overall risk | Top hazard |
|---|---|---|
| Kings County | Inland flooding | |
| Queens County | Inland flooding | |
| New York County | Inland flooding | |
| Suffolk County | Inland flooding | |
| Bronx County | Inland flooding | |
| Nassau County | Inland flooding | |
| Westchester County | Inland flooding | |
| Erie County | Inland flooding |
Neighboring counties
| County | Overall risk | Declarations |
|---|---|---|
| Jefferson County | 17 | |
| Herkimer County | 21 | |
| Franklin County | 16 | |
| Lewis County | 24 | |
| Hamilton County | 14 |
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.