EF1 tornado, Classen Field Airport to Danforth, Illinois, June 25, 2021

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

June 25, 2021

Touchdown

8:06 PM CDT (01:06 UTC)

Lifted

8:11 PM CDT (01:11 UTC)

On the ground

5 minutes

Path length

1.5 miles (2.4 km)

Path width

250 yards (229 m)

Deaths

0

Injuries

0

County

Iroquois County

Touchdown point

40.808, -88.002

Lift-off point

40.821, -87.981

Record number

2106251906-01

10 damage points were recorded along this path by NWS LOT, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 95 mph.

• Visible signs of shingle damage, owner mentioned roof installation was done poorly. Davis station measured 90-95 mph wind gusts.
• Estimated end point of tornado track based on visible damage from survey.
• Estimated starting point of tornado based on spotter video.

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

Scattered thunderstorms moved across portions of east central Illinois on June 25th producing one tornado.

A tornado with peak winds of 95 mph touched down approximately one mile southwest of Danforth, just west of Interstate 57. Storm chasers recorded video of the multi-vortex tornado as it moved near Interstate 57. Minor damage occurred to trees and crops along the path. A few houses suffered minor siding and roof damage and a grain silo was damaged. The tornado lifted near Jefferson and 3rd Streets in Danforth.

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

5 minutes of warning. NWS LOT issued a tornado warning for this county at 01:01 UTC, 5 minutes before the tornado touched down, in force until 01:32 UTC.

The county was under a severe thunderstorm watch, issued at 22:10 UTC and running to 04:00 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 00:57 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 Chicago radar (KLOT), 88 km away, was scanning. The volume nearest the touchdown began at 01:06 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 2021 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

8 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.