Tornadoes · United States · Illinois · 2021

Unrated tornado, Geneseo, Illinois, August 25, 2021

This Unrated tornado ran 0.0 miles across Henry County on August 25, 2021, touching down at 3:39 PM CDT and reaching 10 yards wide. It killed nobody.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  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 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. Unratedthis tornado

    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.

The record

Rating
Unrated
Date
August 25, 2021
Touchdown
3:39 PM CDT (20:39 UTC)
Lifted
3:40 PM CDT (20:40 UTC)
On the ground
1 minutes
Path length
0.0 miles (0.0 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
County
Henry County
Touchdown point
41.400, -90.210
Lift-off point
41.400, -90.210
Record number
2108251439-01

The damage survey

1 damage points were recorded along this path by NWS DVN, in the Damage Assessment Toolkit the survey teams carry.

  • Sheriff Sergeant reported a touchdown of a landspout with damage to crops. EM reported a small area with crops damaged in the middle of the field. EF-unknown is the rating.

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

What the Weather Service recorded

A few severe thunderstorms developed during the mid afternoon hours of August 25. A landspout was witnessed by law enforcement briefly touching down in a field southwest of Geneseo, IL around 3:40 PM CDT. Further to the south, a severe thunderstorm produced large hail and damaging winds. Hail at least golf ball sized was reported and severe wind gusts around 60 MPH resulted in damage to tree limbs, power lines, and shingles. Another separate short lived tornado occurred in Warren County, just east of the town of Berwick, IL.

Sheriff Sergeant reported a touchdown of a landspout with damage to crops. EM reported a small area with crops damaged in the middle of the field. EF-unknown is the rating.

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

The warnings

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.

Issued (UTC)ExpiredProductOffice
20:39 UTC21:15 UTCSevere Thunderstorm WarningDVN
20:43 UTC21:00 UTCTornado WarningDVN
21:11 UTC22:00 UTCSevere Thunderstorm WarningDVN

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 forecast that day

The Storm Prediction Center had this point in a Marginal Risk. The outlook in force was issued at 19:59 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 air that afternoon

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.

Davenport, (KDVN), 12:00Z

8.7 hours before the tornado, 34 km from the path. August 25, 2021.

Skew-T log-pSkew-T log-p diagram, Davenport, at 12:00Z on 2021-08-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 818 joules per kilogram, CIN -238, lifted condensation level 1355 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Davenport, at 12:00Z on 2021-08-25The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity -32 square meters per square second, 0 to 6 km bulk shear 6 knots.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
818 J/kg
Mixed-layer CIN
-238 J/kg
Surface CAPE
394 J/kg
Mixed-layer LCL
1355 m above ground
0-6 km bulk shear
6 kt
0-1 km bulk shear
23 kt
0-1 km storm-relative helicity
-32 m²/s²
0-3 km storm-relative helicity
-10 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.2
0-3 km lapse rate
3.9 K/km

Open this sounding in Storm Lab

Davenport, (KDVN), 00:00Z

3.3 hours after it, 34 km from the path. August 26, 2021.

Skew-T log-pSkew-T log-p diagram, Davenport, at 00:00Z on 2021-08-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2 joules per kilogram, CIN -213, lifted condensation level 1932 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Davenport, at 00:00Z on 2021-08-26The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 9 square meters per square second, 0 to 6 km bulk shear 16 knots.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
2 J/kg
Mixed-layer CIN
-213 J/kg
Surface CAPE
1473 J/kg
Mixed-layer LCL
1932 m above ground
0-6 km bulk shear
16 kt
0-1 km bulk shear
9 kt
0-1 km storm-relative helicity
9 m²/s²
0-3 km storm-relative helicity
58 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.7 K/km

Open this sounding in Storm Lab

The surface observations

Moline (MLI), 25 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
18:40 UTC140° 4 kt1017.9
18:45 UTC170° 4 kt1018.3
18:50 UTC140° 5 kt1017.9
18:52 UTC8873 5 kt1017.9
18:55 UTC110° 2 kt1018.3
19:00 UTC0° 0 kt1017.9
19:05 UTC 1017.9
19:10 UTC0° 0 kt1017.9
19:15 UTC0° 0 kt1017.9
19:20 UTC0° 0 kt1017.9
19:25 UTC0° 0 kt1017.9
19:30 UTC170° 2 kt1017.9
19:35 UTC350° 4 kt1018.3
19:40 UTC320° 2 kt1018.3
19:45 UTC300° 5 kt1018.3
19:50 UTC 11 kt1018.6
19:50 UTC87.871.6290° 11 kt17.111018.6TS
19:52 UTC8769290° 12 kt171018.6TS
19:55 UTC 13 kt1018.3
20:00 UTC 281018.6RA
20:05 UTC 13 kt1017.9+RA
20:07 UTC7770330° 11 kt291017.9+TSRA
20:10 UTC310° 5 kt1017.9+RA
20:13 UTC7869340° 7 kt211018.3RA
20:15 UTC50° 2 kt1018.3-RA
20:17 UTC7769 5 kt1018.3RA
20:20 UTC10° 2 kt1017.9+RA
20:22 UTC7670360° 8 kt1017.9VCTS +RA
20:25 UTC20° 5 kt1017.9-RA
20:30 UTC50° 5 kt1017.9-RA
20:30 UTC7973 5 kt1017.9VCTS -RA
20:35 UTC20° 7 kt1017.9
20:40 UTC10° 8 kt1017.6
20:42 UTC817330° 6 kt1017.9VCTS
20:45 UTC50° 5 kt1017.6
20:50 UTC50° 7 kt1017.6
20:52 UTC827450° 8 kt1017.6VCTS
20:55 UTC40° 5 kt1017.6
21:00 UTC50° 5 kt1017.6
21:01 UTC827450° 6 kt1017.6
21:05 UTC40° 5 kt1017.6
21:10 UTC40° 7 kt1017.6
21:15 UTC50° 5 kt1017.9
21:20 UTC90° 8 kt1017.6
21:25 UTC110° 5 kt1017.3
21:30 UTC70° 5 kt1017.3
21:35 UTC130° 5 kt1017.6
21:40 UTC90° 7 kt1017.3
21:45 UTC80° 5 kt1017.3
21:50 UTC110° 5 kt1017.3
21:52 UTC8374120° 6 kt1017.3
21:55 UTC110° 7 kt1017.3
22:00 UTC100° 7 kt1017.3
22:05 UTC120° 8 kt1017.3
22:10 UTC80° 5 kt1016.9
22:15 UTC80° 5 kt1016.9
22:20 UTC60° 5 kt1017.3
22:25 UTC40° 5 kt1017.6
22:30 UTC50° 5 kt1017.6
22:35 UTC60° 5 kt1017.6

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

The radar

The Quad Cities radar (KDVN), 39 km away, was scanning. The volume nearest the touchdown began at 20:41 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.

What was reported nearby

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

Time (UTC)ReportWhereCountyRemark
20:40 UTCTORNADO4 Ene MorristownHenry, ILTORNADO OBSERVED NEAR THE INTERSECTION OF THE CAMBRIDGE BLACKTOP, HIGHWAY 16, AND NORTH 1800TH AVE JUST SOUTHWEST OF GENESEO.
20:40 UTCTORNADO4 Ene MorristownHenry, ILCORRECTS PREVIOUS TORNADO REPORT FROM 4 ENE MORRISTOWN. SHERIFF SERGEANT REPORTED A TOUCHDOWN OF A LANDSPOUT WITH DAMAGE TO CROPS. EM REPORTED A SMALL AREA WITH CROPS DAMAGED IN THE MIDDLE OF THE FIELD. EF-UNKNOWN IS THE
21:12 UTCHAIL 1.753 W GalvaHenry, IL
21:15 UTCTSTM WND DMGBishop HillHenry, ILEM REPORTS NUMEROUS TREE LIMBS DOWN ACROSS THE COUNTY ALONG WITH POWERLINES DOWN FROM THE WIND. A FEW HOUSES HAD SHINGLES REMOVED AS WELL AS THE STORM MOVED THROUGH THE COUNTY.
21:27 UTCTSTM WND GST 602 N AltonaKnox, IL
21:28 UTCTSTM WND GST 601 Nne NekomaHenry, ILESTIMATED 60 MPH WIND GUST JUST NORTH OF NAKOMA.

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

This ground now

The live radar over the trackEvery 2021 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

The other tornadoes of August 25, 2021

1 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 254:48 PM CDTUnratedWarren, IL0.130

What this means

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.

Sources

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