EF1 tornado, Heman to Argenta, Illinois, April 18, 2024

1. EF065 to 85 mph

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. EF186 to 110 mphthis tornado

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mph

   Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

4. EF3136 to 165 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. EF4166 to 200 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. EF5over 200 mph

   Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

7. Unrated

   The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

Rating

EF1

Date

April 18, 2024

Touchdown

7:27 PM CDT (00:27 UTC)

Lifted

7:32 PM CDT (00:32 UTC)

On the ground

5 minutes

Path length

3.7 miles (6.0 km)

Path width

200 yards (183 m)

Deaths

0

Injuries

0

County

Macon County

Touchdown point

39.930, -89.090

Lift-off point

39.930, -89.020

Record number

2404181827-01

35 damage points were recorded along this path by NWS ILX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 100 mph.

• Debris thrown 2 miles to the SE
• roof thrown into next house
• dugout roof blown off. From drone video Macon Co
• drone footage confirms tornado started in the field to the west. Scour marks across the field from Sw to Ne the east across tree fall area.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

A slow moving frontal system aided the development of supercell thunderstorms by mid-afternoon, which eventually grew upscale into a line segment as they progressed across central and southeastern Illinois during the evening. A total of four tornadoes occurred across Logan and Macon counties in central Illinois. One injury occurred in Logan County when a semi-truck was blown over by one of the tornadoes. In addition to the tornadoes, scattered wind damage also occurred.

The tornado began in Logan County, about 1.5 miles south-southeast of Latham. It progressed east into Macon County, entering the county at the intersection of 2400th Avenue and Heman Street, about 1.75 miles south-southwest of Heman. The tornado uprooted softwood and hardwood trees along 2400th Avenue, which is the county line between Logan and Macon counties. As the tornado progressed east along Heman Street it produced extensive damage to several outbuildings, including knocking down several walls and throwing debris for a mile downstream. The tornado snapped some trees and damaged an outbuilding on 500E Road before dissipating a few hundred yards east of there.

The tornado began about one mile west of Warrensburg along North Kenney Road. It was photographed by the fire chief from Warrensburg as it approached town. The tornado produced roof damage to several homes and damaged numerous trees in Warrensburg. It then traveled along west Illiniwick Road, snapping a couple of large trees before dissipating about a half mile east of north Wyckles Road, which was about 2.5 miles east of Warrensburg.

The tornado began two miles north of Forsyth along east Wise Road, damaging numerous trees around a residence. It progressed eastward, damaging grain bins and six power poles just east of Highway 51 along and north of Wise Road. The tornado continued east along east Wise Road and east Emery Road as it progressed towards Argenta. A semi-truck was blown over on Emery Road near Route 51. Debris was strewn all along the path into the adjacent fields. The tornado eventually dissipated about one mile west of Argenta.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

1 minute of warning. NWS ILX issued a tornado warning for this county at 00:26 UTC, 1 minute before the tornado touched down, in force until 01:00 UTC.

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The Storm Prediction Center had this point in a Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:53 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Decatur (DEC), 19 km from the path, in the two hours either side.

From the Iowa Environmental Mesonet's archive of airport observations.

The Lincoln radar (KILX), 34 km away, was scanning. The volume nearest the touchdown began at 00:28 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

Local storm reports within 60 km of the path, in the three hours either side.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

The live radar over the trackEvery 2024 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

13 more were confirmed in the United States that day.

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.