Jefferson County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Jefferson County: 0.
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. Dec 9, 2009High Wind, Jefferson$100 million
   National Weather Service narrative

   Deep low pressure strengthened as it moved from near Chicago to Quebec. The strong southerly winds ahead of the system downed trees and power lines across the higher elevations of the western southern Tier of New York during the pre-dawn hours. On the New York State Thruway, several tractor trailers were blown over as winds gusted to near 70 mph. As the system passed to the north, winds shifted to southwest and increased. Gusts were measured to 60 mph at the Buffalo International Airport. The winds downed trees and power lines and utilities reported tens of thousands without power.

2. Jan 8, 1998Ice Storm, Jefferson$10.0 million
   National Weather Service narrative

   A devastating ice storm paralyzed Jefferson and parts of Lewis counties. The freezing rain accumulated ice of an inch to an inch and a half thick. The ice coated trees, power lines, and poles and sent them crashing to the ground. Hundreds of thousands of customers were without power for several days to over a week. In Jefferson county, 75% of the county was without power. The county was declared a state and federal disaster area.

3. Dec 27, 2001Heavy Snow, Jefferson$2.0 million
   National Weather Service narrative

   During the night of the 26th and daytime hours of the 27th, lake effect snowbands intensified over northern Jefferson county. On the 28th the snowband settled south across southern Jefferson and Lewis counties. Thunder and lightning were reported during the evening with snowfall rates of two to four inches per hour. The band oscillated north and south across southern Jefferson and Lewis counties through the 28th. By late on the afternoon of the 29th, the band narrowed and moved into southern Lewis and northern Oswego counties. Specific storm totals included: in Jefferson county: Carthage 54"; Redwood 46"; Mannsville 43"; Alexandria Bay 36"; Watertown 30". In Lewis county: Montague…

4. Feb 2, 2007Lake-Effect Snow, Jefferson$1.5 million
   National Weather Service narrative

   This lake effect event started dramatically on the weekend of February 3-4 in association with a surge of arctic air and then continue all week off Lake Ontario as ripples in the low level circulation shifted winds and kept bands of snow moving up and down off Lake Ontario. Lake Erie was in the process of freezing up all week, so although conditions were favorable only an inch or two fell each day after the initial burst on the opening weekend.|The activity began on Saturday morning (the third) on a southwest flow as winds backed ahead of an arctic front. Several inches fell across metro Buffalo as well as Watertown. The front whipped through later in the day with another burst of…

5. Jun 1, 2019Flood$1.5 million
   National Weather Service narrative

   Excessive runoff into the Ottawa River Basin in Canada restricted the outlet of Lake Ontario. This combined with above normal precipitation into the Lake Ontario Basin, record levels on the Great Lakes above Lake Ontario, and higher than normal flows into the lake from the Niagara River pushed the lake to well above normal levels. Over the course of June, new records were broken as the lake pushed to nearly 6 feet above low water datum and eclipsed the levels set in 2017. The lake peaked on June 10.

6. May 20, 2019Lakeshore Flood, Jefferson$1.5 million
   National Weather Service narrative

   Excessive runoff into the Ottawa River Basin in Canada restricted the outlet of Lake Ontario. This combined with above normal precipitation into the Lake Ontario Basin, record levels on the Great Lakes above Lake Ontario, and higher than normal flows into the lake from the Niagara River pushed the lake to well above normal levels. Over the course of May, the levels quickly approached those reached in 2017.

7. Jan 19, 1996Flood, Jefferson$1.0 million
   National Weather Service narrative

   Rapid snowmelt of two to three feet of snow combined with heavy rainfall to produce significant flooding on area creeks and the Black River.

8. Jul 1, 2019Flood$1.0 million
   National Weather Service narrative

   Excessive runoff into the Ottawa River Basin in Canada restricted the outlet of Lake Ontario. This combined with above normal precipitation into the Lake Ontario Basin, record levels on the Great Lakes above Lake Ontario, and higher than normal flows into the lake from the Niagara River pushed the lake to well above normal levels. Over the course of July, water levels began to slowly recede, however after starting the month about 5.5 feet above low water datum, the lake only fell to just below 5 feet above low water datum over the entirety of the month.

9. Nov 22, 2000Heavy Snow, Jefferson$1.0 million
   National Weather Service narrative

   Cold air crossing the warm waters of Lakes Erie and Ontario resulted in lake effect squalls that dropped over two feet downwind of the lakes.Off Lake Erie, the squall developed around midday on the 20th in a southwest flow ahead of a cold front. Snow fell at the rate of two to four inches per hour for several hours. The storm crippled much of the Buffalo metro area. Tens of thousands of people were stranded in autos as city and suburban streets became clogged with traffic and came to a standstill. Three thousand school children were stranded in buses which were unable to complete their routes. Snowfall in this early stage were as high as two feet in a narrow strip about three…

10. Feb 1, 2002High Wind, Jefferson$750,000
    National Weather Service narrative

    An intensifying storm moved across the Great Lakes and lifted northeast to the St. Lawrence Valley. Very strong winds behind the low blasted the region with wind gusts exceeding 55 mph. Trees and power lines were downed by the strong winds. Hundreds of thousands were without power...some for several days. Fallen trees and limbs littered the area and closed roads. Numerous reports of damage to homes and automobiles were received from throughout the area. Driving bans and States of Emergency were declared in several counties. Numerous school districts were forced to close on the first and several remained closed through the beginning of the following week. In Monroe county, two…

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

97°FJul 18, 1953

All-time low

−43°FJan 16, 1994

Warmest night

79°FJul 21, 2011

Coldest day

−12°FJan 3, 1981

Wettest day

4.09 inAug 8, 1981

Snowiest day

45.0 inDec 10, 1995

Hottest year

2012mean 49.3°F

Coldest year

1972mean 42.7°F

Wettest year

201748.79 in

Driest year

197419.94 in

Station Watertown Airport (USW00094790), 311 ft elevation, 6.9 miles from the population centre. Daily records from 1949 to October 26, 2026; 99.8% 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 USW00094790.
• 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.