Merrillville

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond this area.
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.

Flood insurance figures are for Lake County, the county that contains Merrillville.

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 in Lake County, the county that contains Merrillville.

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.

The drought index is for Lake County, the county that contains Merrillville.

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.

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 city centre.
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.

Tsunamis

Tsunami records for Lake County.

1. Places where NOAA's Global Historical Tsunami Database records a tsunami's water arriving, with the greatest height it reached above sea level at the time. Only tsunamis NOAA rates probable or definite are counted. Heights from eyewitness accounts and tide gauges are mixed, and older events are less completely recorded.

NOAA NCEI/WDS Global Historical Tsunami Database, retrieved October 30, 2026.

More event types since 1996

Costliest events since 1996

1. Sep 14, 2008Flood$15.0 million
   National Weather Service narrative

   Record flooding occurred along the Little Calumet River and its tributaries in northwest Indiana. A record crest of 17.32 feet was set at Munster on the 14th. Record flooding also occurred along Hart Ditch. Nearly 190 patients were evacuated from the Munster Med-Inn. Major flooding was reported in Munster with over a thousand homes evacuated as a levee along the Little Calumet River failed. Interstate 80/94 was closed in northwest Indiana when levees were topped by flood waters.

2. Sep 14, 2008Flash Flood$10.0 million
   National Weather Service narrative

   Flash flooding or significant flooding was reported across most of Lake County, including street closures due to flooding, basement flooding and creek, stream and river flooding. Interstate 80/94 was closed due to flooding between Cline and Calumet Avenues. Parts of Interstate 65 were closed due to flooding. In Lake Station, 300 to 400 homes were evacuated. In Merrillivlle, part of 73rd Avenue was washed away, where three cars were damaged. In Dyer, Hart Ditch overtopped its banks which flooded the Briar Ridge Subdivision. Flood waters were several feet deep in parts of Hobart after flood waters overflowed Lake George. Numerous vehicles were submerged or abandoned.

3. Sep 17, 2023Flash Flood$10.0 million
   National Weather Service narrative

   Heavy rain fell across parts of far northwest Lake County causing significant flooding and flash flooding. In Hammond, numerous streets were flooded with cars stranded in the flood waters. At least 500 houses experienced some amount of flooding including basement flooding. The hardest hit area was roughly 3 square miles bounded by the Illinois/Indiana State line on the west, Detroit Street on the south, White Oak Avenue on the east and 137th Street on the north. Rainfall amounts included 4.79 inches in Hammond; 4.53 inches two miles west of East Chicago and 4.36 inches one mile north of Hammond.

4. Sep 13, 2006Flash Flood$8.0 million
   National Weather Service narrative

   Heavy rain fell across parts of northwest Lake County during the middle and late morning hours of September 13th, which caused major and significant flooding. Highland suffered some of the worse flooding with over 1,400 reports of flood damage and 14 homes condemned due to severe damage. At the height of the flooding, 90 percent of the streets in Highland were flooded. School buses were unable to take students home from school and one elementary school had to be evacuated by boat. Over 70 percent of the homes in Highland sustained some damage. Countless streets across northwest Indiana were flooded and impassible. Over 600 homes were damaged by flooding in East Chicago. Flood…

5. Aug 24, 2007Flood$4.0 million
   National Weather Service narrative

   St. Margaret Mercy Hospital in Dyer Indiana suffered significant flooding around noon on Friday, August 24th, about 20 hours after the heavy rains fell, when Hart Ditch overflowed it's banks. Sixty seven patients were evacuated from the healthcare center when it was apparent that floodwaters entering the building would submerge the Hospital���s emergency generators and cutoff the buildings power supply. The first floor suffered significant water damage. More than 150 homes near the creek also sustained some type of flood damage. US 30 at Plum Creek was closed due to flooding. Numerous cars were also damaged by flood waters.

6. Aug 18, 2025Flash Flood$4.0 million
   National Weather Service narrative

   Several instances of flash flooding took place around Gary, Hammond, Whiting, and East Chicago. A sewer storage facility exceeded capacity and overflowed. Multiple basements were flooded in Hammond. Up to three feet of water was reported on Indianapolis Blvd in Whiting from 120th to 129th Street. A portion of US-20 in East Chicago was closed due to flooding. Numerous reports of flooded basements, roads, and yards came out of the east side of Hammond and the west side of Gary. One private weather weather station in the area recorded 5.21 inches of rain while two others nearby recorded over three inches. An estimated 1,000 structures flooded around the area amounting to roughly $4…

7. Jul 20, 2006Strong Wind, Lake$3.0 million
   National Weather Service narrative

   A field house under construction in Hobart was struck by lightning, then blown down by strong winds. The damaged steel frame was in ruins and will set the project back at least 6 months.

8. Aug 15, 2007Thunderstorm Wind$1.0 million
   National Weather Service narrative

   Widespread wind damage occurred in a three to five mile wide path from East Chicago and Gary in northeast Lake County through much of central Lake County to near Winfield and the Lake Porter County line. Numerous large trees uprooted and blown over, some falling onto buildings and cars, causing damage to roofs, siding and windows. Numerous power lines blown down. Trees were blown down on the Indiana Toll Road near milemarker 5 and on Interstate 94 near Broadway. A semi-trailer was blown over at US 30 and Indiana 51. Another semi-trailer was blown over at US 30 and Interstate 65. A large indoor horse riding arena was completed destroyed, but no horses were injured. A Merrillville…

9. Aug 4, 2008Tornado$1.0 million
   National Weather Service narrative

   A tornado touched down just northeast of the Ridge Road and Cline Avenue intersection. Damage occurred at the Griffith Park Plaza Mall where windows were blown out of a row of stores and a portion of a roof was blown off of a vacant store. The damage path continued to the east, behind the mall. Two parked semi-trailers in the back of the mall were shifted eastward while a third was completely knocked over. The area to the east of this mall in the subdivision along and north of 37th Avenue near Lafayette Avenue and Rensselaer Avenue sustained some of the strongest wind damage from this tornado. Two houses on Lafayette Avenue had their roofs blown off with another house on…

10. Aug 23, 2007Thunderstorm Wind$1.0 million
    National Weather Service narrative

    Measured gust to 58 mph at Gary Airport. A hangar under construction was damaged.

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

104°F3 times, most recently Aug 16, 1988

All-time low

−29°FDec 22, 1989

Warmest night

79°FJul 31, 1999

Coldest day

−13°FJan 18, 1994

Wettest day

5.85 inJun 13, 1972

Snowiest day

14.0 inJan 14, 1979

Hottest year

2024mean 53.0°F

Coldest year

2014mean 45.5°F

Wettest year

197257.40 in

Driest year

196427.71 in

Snowiest season

48.5 in2007-08

Station Lowell Wwtp (USC00125174), 665 ft elevation, 15.3 miles from the city centre. Daily records from 1963 to September 30, 2026; 97.5% 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.

Declarations for Lake County.

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.

• 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 USC00125174.
• 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.
• Tsunamis NOAA NCEI/WDS Global Historical Tsunami Database.
• 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.