| January 1967 | Tornado (F3) | not stated | 12 hurt, $250,000 | no account filed |
| June 1998 | Thunderstorm Wind | Shannon | 2 hurt, $8,000 | High winds blew down trees and power lines, and ripped the roof off of a small building. Two people were injured after they were hit by debris. |
| June 2013 | Tornado (EF2) | Savanna | 1 hurt | A NWS Survey team determined that EF2 tornado with maximum winds of 135 mph. The track began 6 miles north of Savanna and ended 4 miles west of Mount Carroll Illinois. The tornado was well defined with significant tree damage. Several farm outbuildings were damaged and one house was pushed off its foundation where the one injury occurred. |
| July 2010 | Flash Flood | Lanark | $10,000,000 | After about a foot of rain in 2 days, creek and small river basins rose rapidly Saturday morning. Numerous rural roads throughout the county suffered from washouts and excessive erosion. Near Argo Fay, Johnson Creek overflowed its banks and closed Big Cut Road.||In Mount Carroll, flooding of the Waukarusa River forced evacuations of about 80 homes, mainly on or near Mill Street. The local fire chief estimated that 80% of Mount Carroll residences had water in their basements.||The Plum River overflowed its banks between Lake Carroll and Savanna, causing extensive and severe damage. Just west of Lake Carroll, a farm house on Polsgrove Road flooded. The resident of the home described the event, saying that around 5 am there was no sign of flooding nearby, and by 7 am water was in the house. ||As the flood waters approached Savanna, the Plum River either overflowed or breached (it is unclear which) a high bank along Scenic Bluff Road, flowing then through the railroad yard to the Mississippi River. Local residents describe water rising about 4 feet in literally a few minutes. In Savanna, an estimated 625 people were evacuated, mainly from the eastern and southern portions of town. Due to the rapidly rising water, first responders in Savanna rescued more than 60 people from their homes. At least 12 homes suffered water up to the first floor and a Swiss Colony factory had several feet of water throughout its facility. Emergency management estimated 10 homes completely destroyed and 75 seriously damaged in Savanna alone. The raging flood waters washed away more than 30 yards of embankment supporting an overpass on the Highway 84 viaduct, washing away two rows of pylons that were supporting the bridge and closing the primary access route south of Savanna indefinitely. Numerous rail cars in the train yard were overturned, some of them washed up against bridges. Both DM&E and Burlington Northern suffered damage to their rail lines. |
| May 1995 | Tornado (F3) | Albany | $2,000,000 | The heaviest damage was in the Twin Oaks area which is five miles east of Fulton. Four homes were destroyed and six homes had major damage. Thirty-six farm buildings were damaged or destroyed on the 15 or 16 farm sites that were hit. Fields and ditches along U.S. 30 looked like a battle zone with twisted metal sticking from the ground. Gary Engelkens survived the tornado inside his mobile home. "I saw it coming, and I thought this was it," he said. He hid under a day-bed when the walls started flying and the bed started shaking. He leaped into the bathroom and then realized there was no roof anymore. "My ears popped and the pressure went up and then pandemonium," he said. The Gary Dykstra farm site, east of Fulton, had nearly all farm buildings destroyed. Gary and his wife were halfway down the basement steps when the tornado hit. The clock stopped at 1825 CDT. Mrs. Dykstra said it got blacker than coal before the tornado struck. Mr. Dykstra said thirty years of work was wiped out and he will not go back into the cattle business. The Jeff Holeginger home on Fenton Road near Fulton was also hit hard. Holesinger saw the tornado moments before it reached his home. Mr. Holeginger said it sounded like a great big freight train going right over the top. The whole house was picked up and dropped down again. Frank George, who farms at the Twin Oaks curve south of Route 30, was in his barn feeding the hogs when the tornado threw the barn across the road. He was not injured. The tornado produced minor damage and emptied itself of debris as it lifted across central Carroll County. |
| July 2010 | Flash Flood | Marcus | $1,000,000 | Heavy rains of 3 to 9 inches fell across Carroll County during the late evening hours of July 22 and through the morning hours of July 23 resulting in flash flooding of much of the county. Several roads across the county, especially the northern half, were closed due to the flash flooding. The Shannon area received over 8 inches of rain during the night and was in need of sludge pumps to assist with the flooding issues in the area. Areas that had never flooded before were flooded. |
| June 1996 | Thunderstorm Wind | Chadwick | $1,000,000 | no account filed |
| April 2010 | Thunderstorm Wind | Milledgeville | $750,000 | Wind gusts estimated to be 70 mph caused a west-facing wall of a church to collapse in Milledgeville, IL around 858 pm April 5. In addition, several 3 foot diameter trees were blown down. Numerous power lines were also knocked down resulting in a power outage to much of the town. Most of the damage was across the northwest part of town and extended about 0.5 miles to the north. |
| April 2013 | Flash Flood | Marcus | $250,000 | Several rounds of heavy rains resulted in some flash flooding of much of Carroll County during the afternoon hours of April 17. |
| July 2011 | Flash Flood | Marcus | $250,000 | Torrential rains of 2 to 5 inches caused some flash flooding across the northern half of Carroll County during the late evening of July 27 and morning of July 28. Several streets in the town of Savanna were flooded forcing the evacuations of 80 residents. Portions of Mount Carroll along the Plum River were also flooded. Both railroad yards in the town were also underwater. |
| July 2011 | Flash Flood | Savanna | $250,000 | A large breach in the Portland Avenue Levee on the Plum River caused some flash flooding in parts of Savanna, IL during the evening of July 28 and early morning hours of July 29. |
| April 2011 | Flood | Marcus | $250,000 | no account filed |
| April 1984 | Tornado (F1) | not stated | $250,000 | no account filed |
| July 2003 | Thunderstorm Wind | Shannon | $200,000 | Numerous limbs down; house under construction had roof torn off |
| April 2010 | Thunderstorm Wind | Milledgeville | $100,000 | Wind gusts estimated to be 60 mph damaged some outbuildings about 1 mile west of Milledgeville, IL around 845 pm April 5. |
| August 2008 | Thunderstorm Wind | Savanna | $100,000 | Wind gusts estimated to be 75 mph blew down numerous trees and power lines across Carroll County around 600 pm August 4. Eight trees were blown down at the county fairgrounds, some of which fell on some cars. Several power outages were observed across the county. |
| May 1999 | Thunderstorm Wind | Shannon | $90,000 | Severe thunderstorm winds first blew apart a hog shed, which caused power lines to fall onto a barn. The barn and about 400 head of hog were lost in the resulting fire. |
| June 2014 | Tornado (EF1) | Thomson | $50,000 | A downburst spawned a brief tornado near Thomson. A old outbuilding was destroyed and extensive damage occurred to large, healthy trees (mostly snapped and some uprooted). Collateral damage to homes and vehicles also occurred from falling trees. Radar indicated gate-to-gate cyclonic shear. The damage path was approximately 3/8 mile wide. The tornado damage was rated EF1 and peak winds were estimated at 100 mph. |
| April 2010 | Lightning | Lanark | $50,000 | A house caught on fire due to a lightning strike in Lanark, IL around 859 pm April 5. |
| April 2010 | Thunderstorm Wind | Milledgeville | $50,000 | Wind gusts estimated to be 70 mph blew down several large trees in Milledgeville, IL around 855 pm April 5. The fallen trees knocked down power lines and destroyed the end of a machine shed. |
| June 1996 | Thunderstorm Wind | Mt Carroll | $50,000 | no account filed |
| May 1996 | Lightning | Mt Carroll | $30,000 | no account filed |
| June 2010 | Thunderstorm Wind | Thomson | $25,000 | Wind gusts estimated to be 70 mph blew trees and power lines down in Thomson, IL around 100 pm CST June 18. Some power outages were also observed. A large tree fell onto a camping trailer at Thomson Causeway. |
| June 2009 | Thunderstorm Wind | Marcus | $25,000 | Wind gusts estimated to be 70 mph blew down some trees and branches about 4 miles north of Savanna, IL around 522 pm June 27. A power outage was also observed. |
| June 2008 | Thunderstorm Wind | Ideal | $25,000 | Winds estimated to be 70 mph blew a tree onto a house near the intersection of Hartman Road and Ideal Road about 4 miles southwest of Chadwick, IL at 10:10 am June 8. |
| September 1959 | Tornado (F2) | not stated | $25,000 | no account filed |
| June 1956 | Tornado (F1) | not stated | $25,000 | no account filed |
| June 1950 | Tornado (F1) | not stated | $25,000 | no account filed |
| September 2000 | Thunderstorm Wind | Mt Carroll | $20,000 | Corn auger blown onto power lines. |
| May 1999 | Heavy Rain | Milledgeville | $20,000 | Localized heavy rain caused basement walls in 2 separate houses to collapse. Up to 4 feet of mud poured into the basements. Damage to each house and the contents was estimated at $10,000. |
| June 2003 | Hail | Thomson | $20,000 | no account filed |
| April 2011 | Thunderstorm Wind | Shannon | $10,000 | Wind gusts estimated to be 65 mph blew down a tree across Ogle Road and Route 72 just east of Shannon, IL around 930 pm CDT April 10. Some power lines were also downed. |
| August 2007 | Thunderstorm Wind | Savanna | $10,000 | Winds estimated to be 70 mph blew down some trees and branches in Savanna, IL. Some landed on power lines and across Scenic Bluff Rd. One tree fell on a car. Delayed report. |
| May 2004 | Thunderstorm Wind | Savanna | $10,000 | Several very large trees down with a carport damaged in the Carroll Heights subdivision up on the bluffs East of the City. |
| June 1999 | Lightning | Savanna | $10,000 | Lightning struck a bell tower at St. Paul's Episcopal Church causing significant smoke and fire damage. |
| August 2005 | Thunderstorm Wind | Thomson | $7,000 | Tree down on a camper. |
| July 2017 | Flash Flood | Chadwick | $5,000 | Local law enforcement reported a guard rail was washed out on Route 40 near Chadwick. |
| July 2017 | Flash Flood | Savanna | $5,000 | Local enforcement reported a mudslide over a portion of Route 84 north of Savanna. The area was deemed unsafe for travel. |
| June 2010 | Thunderstorm Wind | Milledgeville | $5,000 | Wind gusts downed tree limbs in Milledgeville. |
| June 2010 | Thunderstorm Wind | Lanark | $5,000 | Wind gusts downed tree limbs in Lanark. |
| May 2009 | Flash Flood | Lanark | $5,000 | Heavy rains caused some flash flooding of some roads near Lanark, IL during the evening of May 13. Some roads on the south side of town eroded. |
| August 2008 | Thunderstorm Wind | Milledgeville | $5,000 | Wind gusts estimated to be 65 mph blew down some large branches and power lines in Milledgeville, IL at 650 pm August 4. |
| July 2007 | Thunderstorm Wind | Mt Carroll | $5,000 | Winds estimated to be 65 mph blew down several trees onto Cory Rd. Some fuse boxes were damaged. |
| April 2006 | Hail | Milledgeville | $5,000 | also reported by law enforcement. Hail covered the ground. |
| May 2004 | Thunderstorm Wind | Lanark | $5,000 | Six trees down with several power lines. Trees of sufficient size to block several roads. |
| August 2004 | Thunderstorm Wind | Marcus | $5,000 | Bookend vorticy of squall line left Jackson County Iowa and entered Carroll County Illinois around 1900 CST (0100 UTC) near Marcus. Only damage reports received were that of large limbs down that took two people to move on Illinois 84 during 1902-1907 CST. The location is between 0.2 miles north northeast of Marcus near the golf course to 0.4 miles east northeast of Marcus near the northwest edge of Mississippi Pallisades State Park. The sheriff department indicated additional trees down on Senic Ridge Road during 1904-1909 CST. The location is likely between the Jo Daviess/Carroll county line and the northeast edge of Pallisades State Park. Although no additional reports of severe winds were received, KDVN 88D data suggests the potential for additional wind damage across the rest of Washington township, and across Woodland into Freedom townships to a development around Lake Carroll. |
| July 2003 | Thunderstorm Wind | Savanna | $5,000 | Tree limbs down on Illinois 84 |
| September 2000 | Thunderstorm Wind | Mt Carroll | $5,000 | Windows blown out of a building showroom. |
| June 1999 | Thunderstorm Wind | Shannon | $5,000 | Straight line winds gusting over 70 mph damaged a tavern and tore part of a roof off a restaurant. |
| June 1998 | Thunderstorm Wind | Mt Carroll | $5,000 | Branches were broken and large trees were uprooted by strong thunderstorm winds across Carroll County during the early morning hours. At Lake Carroll a large oak tree smashed through the patio door of a home and some of the branches punched through the roof on the garage. Another large tree damaged a home in Lanark and crushed a swing set. |
| July 2003 | Heavy Rain | Marcus | $5,000 | no account filed |
| May 2004 | Hail | Chadwick | $4,000 | Hailed continously for 10 to 15 minutes with hail of all sizes. |
| May 1998 | Thunderstorm Wind | Countywide | $4,000 | Strong thunderstorm winds downed numerous trees and power lines across the county. A roof was blown off a building 1 mile South of Mount Carroll and buildings were blown across the road between Thompson and Savanna. |
| June 2006 | Flash Flood | Savanna Stransky Arp | $3,000 | Railroad underpass on Scenic Bluff Rd was impassable, covered with several feet of water. |
| June 2006 | Flash Flood | Wacker | $3,000 | Railroad underpass on Wacker Road east of town was impassable, covered with several feet of water. |
| July 2006 | Thunderstorm Wind | Lanark | $3,000 | trees down blocking the road |
| August 2005 | Thunderstorm Wind | Milledgeville | $3,000 | A wind gust estimated at 57 knots (65 mph) resulted in 8-10 inch diameter limbs downed that landed up to 10 feet away from their parent tree. A garage door was pushed in on a residence. |
| March 2006 | Hail | Milledgeville | $3,000 | no account filed |
| September 1988 | Tornado (F0) | not stated | $2,500 | no account filed |
| June 2006 | Flash Flood | Savanna | $2,000 | U.S. 52 just south of the business district with a few feet of water across it. |