| June 2015 | Tornado (EF3) | Paytonville | 7 hurt, $25,000,000 | The tornado touched down near Higgins Road and Dupont Road where softwood trees were snapped. The tornado moved east-southeast where trees and power poles were snapped along N Gorman Road. The most significant damage was noted as the tornado crossed S Carbon Hill Road just south of Division Street, entering Coal City. Dozens of homes were heavily damaged in Coal City with three completely destroyed. Two of these homes were well built and had at least part of their structure bolted down to the foundation with bolts secured by nuts. Two high tension metal trusses were downed including one that was crumpled along Hunters Run. Hundreds of trees were snapped or uprooted. Numerous utility poles were downed. Peak winds were estimated to be 160 mph with a max width of three quarters of a mile. The tornado continued into Will County. (Tornado 8a of 10). |
| November 2013 | Tornado (EF2) | Central City | 5 hurt, $10,750,000 | The tornado formed just northwest of the intersection of E Braceville Road and S Carbon Hill Road where several softwood trees were uprooted. The tornado moved northeast just north of E Reed Road where a single family residence sustained visible damage to its exterior while a metal outbuilding sustained roof and exterior wall damage. A single family home sustained considerable damage near the intersection of Berta Road and Spring Road where two people were injured. The tornado continued into a subdivision north of Spring Road where widespread minor damage occurred to several dozen homes. Several homes received more substantial damage though, including partial loss of roofs and second story walls. The tornado continued into Will County around 12:26 PM CST. Maximum wind speeds were estimated to be up to 125 mph. |
| May 2000 | Thunderstorm Wind | Mazon | 2 hurt, $100,000 | Thunderstorm winds knocked down a couple tree limbs in Mazon. One fell on a car. Damage was more extensive in Braceville where many limbs were blown down and large trees, some as old as 150 years, were uprooted. Falling trees and limbs damaged houses, outbuildings, cars, a boat and trailer and power lines. Power poles were snapped off. A semi was blown over on I-55 near Braceville Road, damaging a car and injuring 2 people. At Braceville-Gardner Cemetery, falling trees and uprooted trees damaged tombstones. |
| May 1975 | Tornado (F2) | not stated | 1 hurt, $250,000 | no account filed |
| May 2020 | Tornado (EF0) | Sank Ridge | 1 hurt | A tornado touched down near Interstate 80, about a mile west of the Minooka exit. The tornado blew over a car on Interstate 80, which resulted in one injury. The tornado then moved into southeast Kendall County. |
| November 1965 | Tornado (F2) | not stated | $25,000,000 | no account filed |
| April 2013 | Flash Flood | Nettlecreek | $15,000,000 | The hardest hit areas in Grundy County were Morris, Mazon, and Minooka. Numerous rescues took place, including people trapped in vehicles in rising waters. Forty-four patients at Morris Hospital were evacuated when the lower floor flooded. The aqueduct that carries the I & M canal over Nettle Creek collapsed. South of Morris, Pine Bluff Road was impassable with approximately a foot of water. |
| September 2008 | Flash Flood | Nettlecreek | $5,000,000 | Flash flooding or significant flooding was reported across most of Grundy County, including street closures due to flooding, basement flooding and creek, stream and river flooding. Significant flooding was reported in Coal City. |
| September 2008 | Flood | Morris | $3,000,000 | The Illinois River reached a record crest of 24.84 feet at Morris on the 16th. In Morris, flood waters inundated large areas near the river including the public works facilities and sewage treatment facilities. Water surrounded Ravine Woods apartment complex and residents had to be evacuated. Residents were also evacuated from homes on the east side of Morris along Cemetery Road. |
| July 2003 | Thunderstorm Wind | Morris | $2,500,000 | no account filed |
| August 2007 | Flood | Morris | $2,100,000 | Following a week of heavy rainfall and a storm event rainfall of nearly five inches, significant flooding occurred in the northern two thirds of Grundy County on August 24th, as runoff worked it's way to ditches and streams that quickly overtopped their banks, followed by flooding along larger streams and the Illinois River. Hundreds of basements filled with water, one rehabiliation center was evacuated in Morris, while a berm was built around the Morris hospital to protect the structure and prevent an evacuation and shutdown of that facility. Local officials used more than 22,000 sandbags in an attempt to protect numerous structures from the rushing water. In other locations, piles of gravel were used to divert the flow of water. Many crops were damaged by flowing floodwaters or mud left on plants after the floodwaters receded. An apartment complex was evacuated in Tudor Park due to flooding. |
| August 2012 | Thunderstorm Wind | Morris | $1,500,000 | An estimated 40 to 45 trees were blown down in Morris, including some that fell onto houses and cars. A 26 inch diameter tree fell onto a house on Freemont Avenue. A 250 foot transmission tower along I-80 collapsed. A semi-truck parked at a rest stop was toppled. |
| July 1996 | Flash Flood | Northern | $1,000,000 | no account filed |
| August 1993 | Hail | Morris | $500,000 | no account filed |
| July 2021 | Flash Flood | Kinsman | $300,000 | A slow moving thunderstorm produced torrential rain and flash flooding across portions of western Grundy County. Vegetation was flattened near many creeks and channels due to the fast moving flood waters. Along Armstrong Run, water went over the Indian Trail Road bridge. Damage occurred to the bridge approaches and pavement was missing. A nearby shed was destroyed and a utility pole was toppled. Further northeast, the Kinsman Road bridge over Armstrong Run was also damaged. Significant damage occurred to vegetation including entire trees removed. Damage also occurred to the Dupont Road bridge over Armstrong Run where the approaches suffered significant scouring. Vegetation was flattened and a nearby fence was knocked over with evidence of 1 to 2 feet of flowing water. The Dupont Road bridge over Hog Run was damaged with the approaches washed out. Vegetation was flattened in many locations near Hog Run between Omalley and Grand Ridge Roads. Water rescues were performed during the peak of the flooding near Kinsman and Dupont Roads where at least three vehicles were stuck in flood waters. Rainfall of 6.19 inches was reported during a 3 hour period, four miles northwest of Verona. Rainfall of 4.58 inches was reported during a 4 hour period, three miles east of Seneca. The damage amount was estimated in consultation with local emergency management officials. |
| July 2000 | Flash Flood | Countywide | $250,000 | no account filed |
| May 1988 | Tornado (F1) | not stated | $250,000 | no account filed |
| April 1984 | Tornado (F1) | not stated | $250,000 | no account filed |
| April 1973 | Tornado (F2) | not stated | $250,000 | no account filed |
| June 1999 | Thunderstorm Wind | Morris | $150,000 | Strong winds brought down tree branches and wires. Falling trees caused damage to buildings and at least one vehicle. |
| April 2011 | Hail | Minooka | $100,000 | A severe thunderstorm produced widespread hail up to the size of golf balls across Minooka and surrounding areas including Interstate 80 and Ridge Road. |
| July 2009 | Lightning | Morris | $100,000 | A lightning strike at or near the Grundy County Administration Center damaged portions of the 911 system equipment, Emergency Operations Center equipment and the administration center computer systems. |
| August 2007 | Thunderstorm Wind | Morris | $100,000 | Ten inch diameter tree blown down blocking Southmor Road, south of Morris. Eight inch diameter tree blown down near Jewitt and Center Street. Several tree limbs and power lines blown down across Grundy County. Several 8 to 10 inch diameter tree limbs blown down and a 30 foot section of corn field flattened near Saratoga Road, one mile north of Interstate 80. Damage reported to power lines, structures and crops. |
| October 1996 | Thunderstorm Wind | Countywide | $100,000 | no account filed |
| July 2008 | Thunderstorm Wind | Morris | $90,000 | Wind gusts to 68 and 72 mph were recorded at the Grundy County EOC in Morris. Limbs and wires were blown down along Route 6 west of Morris. Trees were uprooted and tree limbs and power poles were snapped along Saratoga Road northwest of Morris. Trees and wires were down across north and central parts of Morris. Several homes and vehicles were damaged by falling tree limbs. Crops were also flattened. |
| April 2004 | Tornado (F0) | Minooka | $76,000 | The tornado struck an industrial complex. A wastewater treatment building was destroyed, walls were blown out and structural beams were bent, at Tabler Road, south of Route 6. There was damage to overhead doors and an air handling unit was torn from a roof of a building on the east side of Tabler Road. Further east there was damage to walls and roof of an outbuilding. Antennas was blown down at the fire station on Route 6. |
| June 2014 | Thunderstorm Wind | Morris | $75,000 | Straight line winds of 80 to 90 mph caused a tremendous amount of tree damage across all of Morris. Numerous utility poles were snapped and power lines were blown down. Numerous roads were blocked. An estimated 90 percent of the city was without power. Structural damage was observed to a warehouse building on the north side of Morris with significant loss of roof covering. |
| April 1997 | Thunderstorm Wind | Se Part Of Cnty | $70,000 | no account filed |
| June 2013 | Thunderstorm Wind | Minooka | $60,000 | Two semi trucks were blown over on Interstate 80 near Ridge Road. A tree was blown onto a house in Minooka. |
| June 1998 | Thunderstorm Wind | Morris | $60,000 | no account filed |
| June 2015 | Tornado (EF1) | Gorman | $50,000 | The tornado blew off a portion of the roof of a house and snapped a large tree. Peak winds were estimated at 95 mph. (Tornado 7 of 10). |
| June 2015 | Tornado (EF1) | Nettlecreek | $50,000 | This is a continuation of a tornado that began in Lasalle County. This tornado was determined based on reports from trained spotters and photos of the damage. Large trees were snapped and there was minor structural damage to outbuildings. The tornado crossed Interstate-80 near the Seneca Exit. The tornado had peak winds estimated to 90 mph. (Tornado 6b of 10). |
| May 2013 | Lightning | Mazon | $50,000 | A substation was severely damaged by a lightning strike. |
| June 2011 | Thunderstorm Wind | Morris | $50,000 | Several trees and power lines were blown down in Morris. The most significant was on Liberty Street, where a tree fell onto a house causing damage. Another tree fell and blocked Cemetery Road. |
| June 2010 | Thunderstorm Wind | Harrisonville | $50,000 | There was damage to a set of portable bleachers, two portable toilets, bundles of styrofoam insolation, and four 55 gallon trash cans at the high school on Division Street. The windshield of a vehicle was broken by flying debris. Along Oak Street, from Broadway to the railroad tracks, a construction trailer was destroyed, tree limbs were blown down, a tree was uprooted, and there was minor roof damage to a house and a garage. |
| March 2009 | Flood | Nettlecreek | $50,000 | Heavy rain caused ditches, streams and rivers to overbank throughout Grundy County. Runoff washed out several roadways. Numerous homes had basement/crawlspace flooding. Sandbagging took place in many areas of the county. |
| July 2008 | Thunderstorm Wind | Morris | $50,000 | Large branches and wires were blown down. There was some structural damage from tree limbs. |
| February 2008 | Flood | Nettlecreek | $50,000 | Rainfall and melting snow caused flooding across most of Grundy County. Several homes suffered flood damage. |
| July 2008 | Thunderstorm Wind | Morris | $50,000 | Numerous trees, tree limbs and power lines were blown down in Morris. A few trees were uprooted. A large tree fell onto a house and a car on Benton Street, causing significant damage to both. |
| July 2008 | Thunderstorm Wind | Coal City | $50,000 | Large tree limbs and power lines were blown down. Some structural damage was reported from debris. Crop damage was also reported. |
| June 2007 | Thunderstorm Wind | Morris | $50,000 | An area of Morris suffered tree damage and the falling trees and tree limbs damaged several houses. Some trees were 2 to 3 feet in diameter. The area of damage was bounded by Vine Street to the west, the railroad tracks to the north, Jeffereson Street to the south and Washington Street on the east. |
| October 2006 | Thunderstorm Wind | Morris | $50,000 | Trees, tree limbs, and power lines were blown down across much of Grundy County. Widespread crop damage was reported with some damage to out buildings. A garage door was damaged near Dwight and Lowery Roads. |
| July 1999 | Thunderstorm Wind | Minooka | $50,000 | Two miles west of Minooka downed trees destroyed three manufactured homes, damaged several other homes , and caused extensive damage to a number of vehicles. |
| July 1994 | Thunderstorm Wind | Morris | $50,000 | A thunderstorm produced a wind gust to 68 mph at the Grundy County Emergency Services Office. Hail ranging from 0.25 to 0.75 inch in diameter fell in the area. Trees and power lines were damaged by high winds and lightning. Flooding of roads was casued by 1.43 inches of rail falling in 35 minutes. |
| September 2000 | Thunderstorm Wind | Mazon | $50,000 | no account filed |
| May 2008 | Lightning | Morris Muni Arpt | $40,000 | Lightning struck a barn and started a fire. The fire spread to a parked car nearby. |
| August 2002 | Lightning | Morris | $40,000 | no account filed |
| June 2000 | Lightning | South Wilmington | $36,000 | Lightning struck a house, causing a fire. |
| June 1996 | Thunderstorm Wind | Morris | $30,000 | no account filed |
| August 2016 | Flash Flood | Braceville | $25,000 | At intersection of Railroad and McNeil St, water is 2 to 3 feet deep. Estimated 4.50 of rain fell in 90 minutes. Many roads in town are flooded, some significantly. |
| August 2008 | Thunderstorm Wind | Minooka | $25,000 | The roof of a storage building collapsed on Mondamin Street. |
| August 2007 | Thunderstorm Wind | Morris | $25,000 | Cars were reported blown off a road north of Morris. A 62 mph gust was measured at Route 6 and Saratoga, two miles west of Morris. |
| May 2004 | Thunderstorm Wind | Mazon | $20,000 | Numerous large trees were snapped off at about the 20 foot level in an 8 block area. A chain link fence was bent and several roof systems were damaged by trees and branches falling on them. Additionally, Grundy County emergency management reported numerous tree branches and power lines down throughout the county and significant flooding in southwestern portions of Grundy County. Several secondary roads were closed and streams were at bankfull. Standing water was reported in many fields. |
| July 1997 | Thunderstorm Wind | Morris | $20,000 | A strong thunderstorm produced heavy rain and strong winds, with gusts to 78 mph at the Grundy County Emergency Operations Center. Several rooftops were removed on the west side of Morris with the debris landing as much as a block away. Power lines were downed, causing power outages for up to 24 hours. Some trees were uprooted and numerous large tree branches were downed, causing structural and vehicle damage. |
| June 1995 | Thunderstorm Wind | Minooka | $15,000 | Trees were downed and there was some structural damage from thunderstorm winds. |
| June 2017 | Thunderstorm Wind | Morris | $10,000 | A two block area in Morris received widespread tree damage, trees blown down and shingles blown off roofs. |
| August 2015 | Thunderstorm Wind | Central City | $10,000 | Roof off of garage in Central City neighborhood just north of Braceville. Small tree limbs and power lines down in the area. Also, Gardner Fire Department estimated 60 mph winds. |
| July 2012 | Thunderstorm Wind | Minooka | $10,000 | Trees and tree limbs were blown down on the north side of Minooka. One small tree fell onto a house. The roof was torn off a baseball dugout and part of a cinder block wall fell at the Minooka Elementary School. An old fence was uprooted and fell onto a police car at the municipal building. |
| August 2011 | Thunderstorm Wind | Coal City | $10,000 | Winds measured to 64 mph caused a tree to fall onto a house, and another to fall onto the roadway, blocking portions of Kankakee Street. A transformer was also blown down. A large tree limb fell on Division Street and just missed hitting a vehicle. |
| July 2010 | Thunderstorm Wind | Morris | $10,000 | Large tree limbs and power lines were blown down in the Morris and Coal City areas. |