LaSalle County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within LaSalle County: 10.
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.

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 USGS Conterminous (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. Apr 18, 2013Flash Flood$75.0 million
   National Weather Service narrative

   County emergency managers estimated that over 500 buildings were damaged by flooding across La Salle County. In Marseilles, 1500 people were evacuated due to a compromised levee which led to dozens of homes and facilities being flooded along the river front. Several barges broke loose from a tugboat on the Illinois River and rammed into the levee. Five of the eight locks were damaged such that they could not close completely. Flooding occurred in Utica east of Route 178 resulting in evacuations on the I&M Canal. Creeks were reported out of their banks in Mendota. A woman was killed on Route 351 as it passes over the Illinois River near Peru. She drove around barricades and became…

2. Jun 5, 2010Tornado$7.0 million
   National Weather Service narrative

   Shortly after the Magnolia, IL tornado lifted, the same supercell thunderstorm went on to produce another tornado near the Marshall and LaSalle County line. National Weather Service damage survey teams found the damage from this tornado began just west of 2900 E Road and about one quarter mile south of 1250 N Road, or N 12th Road, which is the road that marks the county line. The tornado crossed north of 1250 N Road at Interstate 39. See Stormdata for Illinois, Central for the beginning of this tornado. ||This tornado continued eastward tracking along and just north of 12th Road, producing primarily EF0 to EF1 intensity damage, largely in the form of downed trees, power lines, and…

3. Sep 15, 2008Flood$5.0 million
   National Weather Service narrative

   The Illinois River reached a record crest of 33.79 feet at LaSalle on the 16th. Major flooding occurred along the river in LaSalle County. In Marseilles, flood waters inundated Illini State Park and nearby areas. Flood waters inundated the Peru power plant. Brunner and Water Streets were closed due to flooding. Navigation on the river was halted as most lock facilities were submerged. The Interstate 39 bridge was the only one open as State Highways 251, 351, and 178 were closed. Homes and businesses in Utica were flooded. In Ottawa, 89 residents of a nursing home were evacuated. Dee Bennett Road between Ottawa and Utica was closed. Central Elementary School in Ottawa was…

4. Sep 14, 2008Flash Flood$5.0 million
   National Weather Service narrative

   Flash flooding or significant flooding was reported across much of LaSalle County, including street closures due to flooding, basement flooding and creek, stream and river flooding. Numerous houses were under water in the northwest and southwest part of Sheridan which is near the Fox River. Several evacuations were conducted. Northeast of Utica, County Roads E 10th and and N 31st were closed with up to one foot of water covering the roads. A canoe launch area in Streator along the Vermillion River was submerged. Flooding was reported in Wedron, Utica, Earlville and Marseilles. The wastewater treatment plant in the City of LaSalle suffered significant damage. Numerous vehicles were…

5. Jul 12, 2021Flash Flood$1.2 million
   National Weather Service narrative

   A slow moving thunderstorm produced torrential rain and flash flooding across portions of eastern La Salle County including in Seneca. Vegetation was flattened near many creeks and channels due to the fast moving flood waters. Along Hog Run, vegetation was flattened near North 21st Road with debris near the road. Along North 2350th Road near Armstrong Run, flood waters flowed over the roadway with debris in the channel. North La Salle Road was flooded, just south of Dupont Road with debris piled on the side of the road along with erosion in the channel. There was substantial deposition of sediment from a nearby sand and gravel facility across Dupont Road near Deadly Run. A…

6. Aug 24, 2007Flood$1.0 million
   National Weather Service narrative

   Heavy rain throughout the month over southern Wisconsin and northern Illinois caused the Fox River to crest at 17.33 feet at Dayton on August 24. This was more than 5 feet above flood stage. Basements and garages were flooded along the river in Wedron and Ottawa.

7. Jul 13, 2015Hail$1.0 million
   National Weather Service narrative

   There were numerous reports of hail of up to 3.75 inches in diameter across portions of Marseilles. A picture of the largest hail was received via social media. A car dealership reported 40 damaged cars, 10 of which had shattered windshields. A greenhouse was shattered. The siding on numerous houses was damaged.

8. Jun 30, 2014Tornado$250,000
   National Weather Service narrative

   An aerial survey from local media showed clear convergent swirling and scarring near Earlville. A short lived tornado touched down embedded within a larger area of straight line wind damage. Numerous trees were blown down with damage to roofs and a garage blown out on the south and southwest portions of town. Maximum winds were estimated to 110 mph.

9. Jan 29, 2008High Wind, La Salle$250,000
   National Weather Service narrative

   High winds caused damage across LaSalle County. Part of a tree was blown down onto a porch and a house in Mendota causing damage to both. Part of a carhop awning was blown down in Oglesby. A roof was blown off a building and power lines were blown down in Marseilles.

10. Aug 23, 2007Flash Flood$250,000
    National Weather Service narrative

    Several inches of flowing water over Route 23 in and north of Ottawa. Flash flooding occurred in Utica as Clark Run Creek overflowed its banks sending floodwaters down the main part of town. According to reports, about 45 residents responded to a request for evacuation. Widespread basement flooding was reported in the Peru-La Salle areas. Many streets and county roads flooded within La Salle County. Flash flooding was also reported in Triumph, Naplate, and Grand Ridge in La Salle County. Dee Bennet Road near Buffalo Rock State park was closed due to flooding. Portions of Route 178 were also closed.

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

112°F2 times, most recently Jul 14, 1936

All-time low

−26°F2 times, most recently Jan 30, 2019

Warmest night

81°FJul 18, 1942

Coldest day

−11°FDec 22, 1989

Wettest day

8.77 inJul 14, 1958

Snowiest day

14.0 inJan 23, 1898

Hottest year

1922mean 54.9°F

Coldest year

2014mean 47.0°F

Wettest year

190255.45 in

Driest year

195622.06 in

Snowiest season

72.6 in1925-26

Station Ottawa 4SW (USC00116526), 545 ft elevation, 2.0 miles from the population centre. Daily records from 1892 to October 27, 2026; 97.2% 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 USC00116526.
• 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.