Northumberland County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Northumberland County: 2.
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.

Mapped landslides

Mapped by NASA (1).

1. Landslides mapped in the USGS compilation of landslide inventories across the United States (version 3.0, 2025), rated probable or better. The compilation joins inventories made by federal and state agencies for different purposes and areas, so the number mapped in a county reflects how closely it has been surveyed as much as how often its slopes fail. An area with few records may simply not have been mapped. Deaths are as recorded in the inventories; a slide listed in two inventories is counted once.

USGS Landslide Inventories across the United States, version 3.0, retrieved October 27, 2026.

More event types since 1996

Costliest events since 1996

1. Sep 7, 2011Flood$600,000
   National Weather Service narrative

   The Susquehanna River at Danville crested above moderate flood stage at 31.55 feet. This was the 2nd highest crest on record. The West Branch Susquehanna River at Lewisburg crested in moderate flood stage at 25.91 feet. Flood stage is 18.0 feet. This was the 11th all time highest crest. The West Branch Susquehanna River at Milton crested in major flood stage at 26.6 feet. Flood stage is 19.0 feet. This is the 10th all time highest crest. The West Branch of the Susquehanna River at Watsontown crested in moderate flood stage of 26.7 feet. Flood stage is 20.0 feet. This is the 8th highest crest all time.||Heavy rainfall from the remnants of Tropical Storm Lee resulted in extensive…

2. Apr 23, 1996Thunderstorm Wind$100,000
   National Weather Service narrative

   The roof of a building was lifted and about 15 autos were damaged in a parking lot in Sunbury as a thunderstorm moved through the area.

3. Jun 28, 2016Thunderstorm Wind$100,000
   National Weather Service narrative

   A severe thunderstorm produced winds near 90 mph. Numerous trees were knocked down. Four homes sustained damage from falling trees. A car and truck were destroyed by falling trees.

4. Jun 30, 2015Tornado$50,000
   National Weather Service narrative

   An EF1 tornado was confirmed south of Riverside...with multiple trees down and damage to a small barn and a home. A shed was destroyed and a car was damaged by flying debris. Maximum estimated winds were 100 mph, classifying this as an EF1 tornado.

5. Apr 29, 2025Thunderstorm Wind$50,000
   National Weather Service narrative

   A line of severe thunderstorms producing wind gusts estimated at 70 mph knocked down trees and wires in Sunbury. The wind caused a building to collapse on Julia Street.

6. Sep 7, 1999Flash Flood$30,000
   National Weather Service narrative

   Dennis caused flooding in Watsontown and Milton in the early morning hours as heavy rains fell across the area.

7. Apr 28, 2011Thunderstorm Wind$30,000
   National Weather Service narrative

   Thunderstorm winds estimated near 70 mph knocked down several trees and damaged a trailer in Dalmatia. Two people were extracted from the trailer but sustained no injuries.

8. May 23, 2011Tornado$25,000
   National Weather Service narrative

   The NWS State College confirmed a EF1 tornado in Northumberland County. The tornado touched down around 1739 EDT near Winfield in Union County and traveled east across the Susquehanna River approximately 1 1/4 miles between 1740-1741 EDT before lifting near PA 147 around 1742 EDT. The tornado first touched down west of 165 Grover Road in Union County. Damage was primarily snapped and uprooted trees. The tornado moved down the hill crossing US-15 and River Breeze Avenue before moving over the Susquehanna River into Northumberland County. Tree damage along River Breeze road caused damage to two homes, and trees were snapped on the south end of an island near the east shore of the…

9. Jul 31, 2009Flash Flood$25,000
   National Weather Service narrative

   Heavy rain produced flash flooding just north of Watsontown in Delaware Township along Route 405. A trailer park was inundated by up to six feet of water with at least ten trailers flooded. One resident was temporarily evacuated.

10. Jun 19, 2025Thunderstorm Wind$25,000
    National Weather Service narrative

    A severe thunderstorm, producing wind gusts estimated near 70 mph, knocked down and uprooted multiple trees in Milton. Shingles were also blown off on some residences in Milton.

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

105°F3 times, most recently Jul 17, 1988

All-time low

−27°FJan 14, 1912

Warmest night

77°FJul 12, 1916

Coldest day

0°FJan 20, 1994

Wettest day

6.22 inSep 18, 2004

Snowiest day

28.0 inApr 11, 1894

Hottest year

1913mean 53.8°F

Coldest year

1978mean 48.1°F

Wettest year

201170.02 in

Driest year

193024.32 in

Snowiest season

84.5 in1995-96

Station Selinsgrove 2 S (USC00367931), 420 ft elevation, 11.2 miles from the population centre. Daily records from 1894 to October 22, 2026; 99.7% 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 USC00367931.
• 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.
• Landslides USGS Landslide Inventories across the United States, version 3.0 (2025).
• 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.