EF1 tornado, Williamsfield, Illinois, July 15, 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

July 15, 2024

Touchdown

8:07 PM CDT (01:07 UTC)

Lifted

8:08 PM CDT (01:08 UTC)

On the ground

1 minutes

Path length

1.3 miles (2.0 km)

Path width

150 yards (137 m)

Deaths

0

Injuries

0

County

Knox County

Touchdown point

40.960, -90.020

Lift-off point

40.950, -90.000

Record number

2407151907-01

43 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 107 mph.

• A dozen pine trees snapped.
• 6 more pine trees snapped.
• Multiple trees snapped and one uprooted.
• Multiple trees snapped and branches snapped.

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

On the evening of July 15, 2024, a derecho brought very strong winds, several tornadoes, and heavy rainfall to a good portion of the Midwest. Thunderstorms initiated over central Iowa during the late afternoon hours then quickly spread east-southeast through southern Wisconsin, the northern half of Illinois, southern Michigan, and the northern/central Indiana. The event produced significant tree damage, some structural damage, and 10 tornadoes within the NWS Lincoln County Warning Area, most of which were rated EF-0 or EF-1. Back building of storms into the morning of July 16, 2024, brought very heavy rainfall and flash flooding near and south of a Galesburg to Sullivan line. The heaviest rain fell over Fulton and Mason counties where 4-8 was reported, necessitating some road closures and producing damage to roadways in Fulton County. One indirect death occurred in Peoria County as part of this thunderstorm event.

This short tornado touched down two miles north of Williamsfield, west of North State Route 180, and moved southeast for one mile while producing significant tree damage along Route 180 and in the field to the east. Many of the trees were blocking Route 180. The tornado lifted just south of County Road 1660 North.

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

12 minutes of warning. NWS ILX issued a tornado warning for this county at 00:55 UTC, 12 minutes before the tornado touched down, in force until 01:30 UTC.

The county was under a tornado watch, issued at 23:55 UTC and running to 03:26 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 Moderate Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 00:47 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.

The Quad Cities radar (KDVN), 87 km away, was scanning. The volume nearest the touchdown began at 01:05 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

61 more were confirmed in the United States that day.

All 62 of them

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.