EF2 tornado, Green Rock to Atkinson, Illinois, April 4, 2023

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 mph

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

3. EF2111 to 135 mphthis tornado

   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

EF2

Date

April 4, 2023

Touchdown

10:15 AM CDT (15:15 UTC)

Lifted

10:19 AM CDT (15:19 UTC)

On the ground

4 minutes

Path length

2.8 miles (4.5 km)

Path width

600 yards (549 m)

Deaths

0

Injuries

0

County

Henry County

Touchdown point

41.430, -90.120

Lift-off point

41.420, -90.070

Record number

2304040915-01

7 damage points were recorded along this path by NWS DVN, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 115 mph.

• 5 to 6 pines uprooted at location. Trees feel perpendicular to the gust front.

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

There were two rounds of severe thunderstorms on April 4th. The first round in Illinois occurred during the morning hours. These storms developed in eastern Iowa and moved into northwest Illinois by mid morning. Despite the elevated nature of the storms and a very stable low level, a very strong downdraft surge occurred south of the hail core over the Illinois side of the Quad Cities metro, with the Quad City Airport ASOS measuring a wind gust near 90 MPH. Extensive damage occurred from Rock Island to Colona IL to buildings, trees and power poles, with some structures seeing ripped-off roofs. A survey team determined a brief tornadoes touched down in Moline, Colona, and near Geneseo Illinois.

A brief tornado developed Tuesday morning in Colona, Illinois, and was embedded in a broader swath of damaging straight line winds. The tornado was on the ground for 0.4 miles and west 50 yards wide. the peak estimated winds were 115 MPH. The tornado moved through the northern portion of Colona, and was on the ground for about a half mile. The tornado was captured on video, ripping the entire roof off a gas station and tossing it into a brick building just to the south. The front wall of the building also collapsed. The tornado also uprooted trees, and caused minor house damage.The tornado was rated a low-end EF-2, with maximum winds around 115 mph.

A localized rear flank downdraft (RFD) surge on the south side of a broader high precipitation(HP) supercell RFD caused a tornado to form. The EF2 tornado with 115 MPH winds began just east of Geneseo. The path had sporadic damage and based on eye-witness reports it was a multiple vortex tornado. Different suction vortices caused damage to farm buildings, trees, silos and houses along its 2.8 mile long path. Many trees were uprooted or snapped in different directions. Most houses had uplift of shingles. Towards the end of the path, the tornado strengthened just before it occluded. EF2 damage was found here as a power pole was snapped, 4 farm outbuildings were destroyed and the roof on the house was lifted then put back down on the house. Many thanks to Henry County OEM for helping with the survey.

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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

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 Moderate Risk, with a 0.15 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 12:54 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.

Moline (MLI), 34 km from the path, in the two hours either side.

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

The Quad Cities radar (KDVN), 45 km away, was scanning. The volume nearest the touchdown began at 15:12 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 2023 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

10 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.