Lewis County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Lewis 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.

Costliest events since 1996

1. Jan 8, 1998Ice Storm, Lewis$2.0 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.

2. Dec 28, 2001Heavy Snow, Lewis$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…

3. May 22, 2014Flash Flood$1.5 million
   National Weather Service narrative

   A weak surface low drifted across the North Country and produced slow moving thunderstorms. The thunderstorms produced three-quarter inch hail near Turin and Port Leyden. The storms also dropped very heavy rains���radar estimating between eight and nine inches in some locations. The Village of Port Leyden in the Town of Leyden was hardest hit. More than a dozen roads in the Town were completely washed out with numerous others damaged. A sewer line and secondary water line were destroyed with a ���Boil Water��� advisory issued. About a dozen homes were damaged. A basement wall collapsed in one resulting in a total loss. Several dozen people had to be evacuated at…

4. Aug 7, 2023Tornado$1.5 million
   National Weather Service narrative

   The National Weather Service in Buffalo completed a storm survey in Lewis County for damage that is confirmed to be tornadic from Monday evening. Initial damage from the tornado occurred in the Town of Lewis to the west of West Leyden along Mud Lake Road that included uprooted and snapped hardwood trees, significant damage to two homes that included roof uplift and near total removal, a wall blowout of a garage, and the complete destruction and shift from the foundation of a barn. Damage in the initial portion of the track generally peaked at EF-2. The tornado then continued northward and crossed Fish Creek Road with damage to another home that removed the roof and caused…

5. Apr 28, 2011Flood$1.1 million
   National Weather Service narrative

   After near record-setting spring rainfall, a warm front brought two to four inches of rain to the eastern Lake Ontario Region. The runoff resulted in flooding across the Black River basin, including the Black River and some of its major tributaries. Numerous roads were closed, some damaged or washed out. A few examples included: South Main Street in Carthage, East Martinsburg Rd, Ridge Rd, Merz Rd, Zecher Rd, Smith Rd, Moose River Rd, River D, Shibley Rd and Milkhouse Rd. The Black River at Boonville crested at 10.7 feet around 3am on the 29th. Flood stage is 10 feet. The Black River at Watertown crested at 12.7 feet around 9am on the 30th. Flood stage is 10 feet. A 67-year-old…

6. Nov 22, 2000Heavy Snow, Lewis$500,000
   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…

7. Nov 21, 2000Heavy Snow, Lewis$500,000
   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…

8. Nov 20, 2014Lake-Effect Snow, Lewis$300,000
   National Weather Service narrative

   Lake effect snows developed during the early morning hours of Thursday (20). The band initially started over Kingston Ontario and parts of southern Quebec shortly after midnight Wednesday night, then as the southwest flow veered during the wee hours of the morning, the band shifted south and east across Jefferson County. By daybreak Thursday, twin bands of moderate to heavy snow were found east of Lake Ontario, with one centered over northernmost Jefferson County and the other over the northern slopes of the Tug Hill and northern Lewis County. As the southern band pushed south off the lake during the course of Thursday morning, the northern band drifted south to the northern…

9. Feb 1, 2002High Wind, Lewis$300,000
   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…

10. Jul 8, 2014Tornado$250,000
    National Weather Service narrative

    A NWS survey team confirmed an EF1 tornado.

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°FJul 2, 1931

All-time low

−40°FDec 20, 1942

Warmest night

78°FAug 2, 2006

Coldest day

−16°FDec 20, 1942

Wettest day

6.02 inJul 11, 2024

Snowiest day

30.5 inDec 11, 2009

Hottest year

2024mean 47.8°F

Coldest year

1904mean 40.1°F

Wettest year

201755.64 in

Driest year

193424.36 in

Snowiest season

251.0 in1970-71

Station Lowville (USC00304912), 863 ft elevation, 1.7 miles from the population centre. Daily records from 1892 to October 27, 2026; 99.4% 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 USC00304912.
• 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.