St. Lawrence County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within St. Lawrence County: 1.
2. Weak tornadoes were under-recorded before Doppler radar coverage became national in the early 1990s, so earlier decades read low. Ratings use the Fujita scale before February 2007 and the Enhanced Fujita scale after.

Storm Prediction Center severe weather database, 1950 to 2025.

Every storm within 100 miles

1. Tropical storms and hurricanes (34 kt or more, still tropical) at closest approach. Post-tropical remnants with gale-force winds are listed but not counted. Direct: track within 50 miles; near: within 100 miles. Distance is measured to the county boundary for counties and to the city centre for cities, using positions interpolated hourly between HURDAT2 fixes.

National Hurricane Center HURDAT2, 1851 to 2025.

Smoke overhead

1. A smoke day is a date on which a smoke plume traced by NOAA Hazard Mapping System analysts from satellite imagery covered this place's point (the county's population centre or the city centre). Counts here are of medium or heavy smoke. Since 2018 analysts have often drawn light smoke as one area over most of the continent, so light-smoke counts are not comparable from year to year. The plumes show smoke anywhere in the air above, not air quality at the ground, and smoke hidden by cloud is missed.

NOAA Hazard Mapping System smoke analysis, 2011 to 2026, retrieved October 30, 2026.

Claims by ZIP code

This product uses the Federal Emergency Management Agency's OpenFEMA API, 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).

OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026. NOAA Storm Events through 2026.

River crests

River gauges

1. Crests are the highest and the recent crests the National Weather Service lists for each river gauge in the county that has a flood stage, not every flood. Flood categories use each gauge's current flood stages; crests from before levees, dams or channel changes may not be comparable. Crests measured on an old datum are left out of the rankings.

NOAA National Water Prediction Service gauge records, retrieved October 30, 2026.

1. The Palmer Drought Severity Index is computed by NOAA each month from the county's average temperature and precipitation, relative to the county's own climate. Zero is normal; -3 or lower is severe drought and -4 or lower extreme drought. It describes the long-term balance of moisture, not water supply or crop losses.

NOAA NCEI nClimDiv county Palmer Drought Severity Index, 1895 to September 2026, issued October 6, 2026.

Every earthquake of magnitude 4 or more within 50 miles

1. Earthquakes of magnitude 2.5 or more in the USGS Comprehensive Catalog since 1900. Within 50 miles means the epicentre lies within 50 miles of the county boundary (or inside the county).
2. Small earthquakes were under-recorded before the modern seismic networks of the 1970s and are still missed in remote areas, so early decades read low. Magnitudes are as the catalogue reports them and mix scales (moment, local and body-wave).

USGS ANSS Comprehensive Earthquake Catalog, 1900 to present, retrieved October 30, 2026.

More event types since 1996

Costliest events since 1996

1. Apr 15, 2014Flood$4.1 million
   National Weather Service narrative

   Heavy rainfall and snowmelt combined to produce flooding across St. Lawrence County. The Grass and St. Regis Rivers were particularly hard hit, and the Oswegatchie and its tributaries continued to run high from flooding in the previous week. Along the St. Regis, two homes were evacuated in Brasher Center, and areas in Winthrop and Brasher Falls were flooded. In Brasher Center, the Main Street Bridge and County Rte 53 were closed. Throughout Stockholm other bridges over the St. Regis were closed due to flooding, and State Rte 420 Extension and Barnage Road were closed. On the Grass River, several cottages were surrounded by water in Madrid along County Route 36. Elsewhere across…

2. Jan 6, 1998Ice Storm, Northern St. Lawrence$3.0 million
   National Weather Service narrative

   A storm system moved from the Tennessee Valley on Wednesday (January 7) and Thursday (January 8) into New England thereafter. A cold front across New England and New York associated with an Arctic High Pressure system across Canada resulted in a flow of low level cold air into northern New York. Warm moist air riding over this low level cold air resulted in a major ice storm across northern New York. During Friday afternoon (January 9), a few thunderstorms with gusty winds and small hail moved across the Champlain Valley of northern New York. Ice accumulations during this event were generally between 1 and 3 inches with the greatest amounts along the New York and Canadian border…

3. Aug 9, 2024Flash Flood$3.0 million
   National Weather Service narrative

   Emergency Mgmt. reported widespread flash flooding across the area with numerous roads closed or washed out due to severe flash flooding. This included, but was not limited to US Route 11 in numerous locations. Some homes and bridges were also damaged with a few swift water rescues noted. The hardest hit areas were around Canton, Colton, Potsdam and Stockholm.

4. Aug 9, 2024Flood$2.0 million
   National Weather Service narrative

   Numerous flooding across St. Lawrence county as the results of heavy tropical rains (4 to 6+ inches) from Post Tropical Debby. In addition to flash flooding reports, there were numerous inundation, basement and other flooding.

5. Aug 9, 2024Flash Flood$1.5 million
   National Weather Service narrative

   Emergency Mgmt. and Dept. of Highways reported numerous roads closed or damaged due to flash flooding in the towns of Gouverneur, Fowler, Edwards and Hermon. This included, but was not limited to Route 58.

6. Apr 28, 2011Flood$1.0 million
   National Weather Service narrative

   Runoff from heavy rain and snowmelt caused flooding on the Raquette River. The river gage on the Raquette at South Colton New York exceeded its flood stage of 10.0 feet at 16:02 EST on April 28, and crested at 11.27 feet at 04:45 EST on April 29. The gage on the Raquette at Piercefield exceeded its flood stage of 12.5 feet at 00:07 April 29, and crested on May 1 at 09:15 EST. There was widespread flooding of low lying property, homes and businesses along the Raquette through Piercefield, South Colton, Colton, Potsdam, and Norwood. Flooding continued into May.

7. Dec 20, 2013Ice Storm, Northern St. Lawrence$1.0 million
   National Weather Service narrative

   Freezing rain accumulated over an inch, along with more than an inch of sleet across northern St. Lawrence county causing numerous vehicle accidents, tree and utility line damage.

8. Dec 20, 2013Ice Storm, Southwestern St. Lawrence$750,000
   National Weather Service narrative

   Freezing rain accumulated between 1 and 1.5 inches across southwest St. Lawrence county causing numerous vehicle accidents, tree and utility line damage.

9. Aug 9, 2024Flash Flood$500,000
   National Weather Service narrative

   Tribal Emergency Mgmt. reported flash flooding in and around Hogansburg, NY due to excessive rainfall. Numerous other locations of flash flooding were observed in the towns of Bombay, Helena and Ft. Covington. Locations included, but were not limited to NY State Route 37 and Beaver Meadow Rd.

10. Sep 16, 2005Flash Flood$500,000
    National Weather Service narrative

    The northeast US was impacted by 2 weather systems on September 16th and 17th. A storm moved northeast along a frontal boundary, from the Ohio valley on the 16th and passed across northern New York the morning of the 17th. In addition, moisture from Tropical Storm Ophelia impacted the area. Steady rain with scattered thunderstorms overspread northern New York on the afternoon of the 16th into the late night hours. Specifically, across the southern half of St Lawrence county, between 3 and 5 inches of rain fell. When the entire overnight period is added into the afternoon rainfall, 6.46 inches of rain was measured in Gouverneur, NY. Flash flooding was reported with road closures in…

1. Storm Events records before 1996 cover only tornadoes, thunderstorm wind and hail. Damage figures are as reported by the National Weather Service at the time, not adjusted for inflation.

NOAA NCEI Storm Events Database, 1950 to 2026, issued October 26, 2026.

All-time high

100°FAug 1, 1975

All-time low

−44°FJan 15, 1957

Warmest night

78°FAug 28, 1977

Coldest day

−18°FJan 15, 1957

Wettest day

4.97 inSep 14, 1979

Snowiest day

17.0 inApr 22, 1993

Hottest year

1998mean 48.5°F

Coldest year

1972mean 41.3°F

Wettest year

199347.35 in

Driest year

202524.11 in

Snowiest season

137.2 in1970-71

Station Massena International Airport (USW00094725), 200 ft elevation, 24.3 miles from the population centre. Daily records from 1948 to October 26, 2026; 98.9% of days in the last 30 years are complete. Records at a single station can differ from a city’s official threaded record, which may combine several stations.

NOAA NCEI Global Historical Climatology Network Daily.

This product uses the Federal Emergency Management Agency's OpenFEMA API, 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).

OpenFEMA Disaster Declarations Summaries, retrieved October 30, 2026. Statewide declarations are not listed.

Neighbouring counties

• Tornadoes NOAA Storm Prediction Center severe weather database, through 2025.
• Tropical cyclones NOAA National Hurricane Center HURDAT2 (Atlantic; Northeast and Central Pacific), through 2025.
• Wildfire USGS/USFS Monitoring Trends in Burn Severity, through 2026.
• Storm events NOAA NCEI Storm Events Database, through 2026.
• Flood insurance OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026.
• Declarations OpenFEMA Disaster Declarations Summaries v2, retrieved October 30, 2026.
• Weather records NOAA NCEI Global Historical Climatology Network Daily, station USW00094725.
• River crests NOAA National Weather Service, National Water Prediction Service river gauges, retrieved October 30, 2026.
• Drought NOAA NCEI nClimDiv county Palmer Drought Severity Index, through September 2026.
• Smoke NOAA NESDIS Hazard Mapping System smoke analysis, retrieved October 30, 2026.
• Earthquakes USGS ANSS Comprehensive Earthquake Catalog (ComCat), retrieved October 30, 2026.

Joins, thresholds and known limits are set out in the methodology. Found an error? Report it. Page built October 30, 2026.