Tornadoes · United States · Iowa · 2026

EF0 tornado, Clinton County, Iowa, August 11, 2026

This EF0 tornado ran 0.3 miles across Clinton County on August 11, 2026, touching down at 8:29 AM CDT. It killed nobody.

Preliminary. This is NWS DVN's damage survey, filed in the Damage Assessment Toolkit. The rating, the path and the casualties are the survey's and can change while it is revised. The Storm Prediction Center compiles the official record of 2026 from these surveys and publishes it in the spring of 2027; this page moves to that tornado's permanent address when it does.

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 mphthis tornado

    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. 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.

The survey

Rating, as surveyed
EF0, preliminary
Date
August 11, 2026
Touchdown
8:29 AM CDT (13:29 UTC)
Lifted
8:30 AM CDT (13:30 UTC)
On the ground
1 minutes
Path length
0.3 miles (0.6 km)
Path width
0 yards (0 m)
Deaths
0
Injuries
0
County
Clinton County
Touchdown point
41.815, -90.548
Lift-off point
41.819, -90.551
Highest wind the damage implies
85 mph
Surveyed by
NWS DVN
Survey last edited
August 13, 2026
Record number
None yet. SPC numbers 2026 in the spring of 2027.

What the survey found

An EF0 tornado, with max wind speeds of 85 MPH, caused damage to trees and houses across its half-mile path. The tornado first caused some minor shingle damage to a home before crossing 14th Avenue. Then, damage to a few more houses was seen, including portions of a roof peeled off one house and damaged awning to another. As the tornado crossed 1st Street, it also damaged the tops of some trees and blew the branches southeastward.

Written by NWS DVN in the NWS Damage Assessment Toolkit. A survey is revised as better evidence arrives.

The warnings

28 minutes of warning. NWS DVN issued a tornado warning for this county at 13:01 UTC, 28 minutes before the tornado touched down, in force until 13:45 UTC.

The county was under a severe thunderstorm watch, issued at 12:23 UTC and running to 16:22 UTC.

Issued (UTC)ExpiredProductOffice
12:23 UTC16:22 UTCSevere Thunderstorm WatchDVN
12:59 UTC14:00 UTCSevere Thunderstorm WarningDVN
13:01 UTC13:45 UTCTornado WarningDVN
13:20 UTC14:03 UTCSevere Thunderstorm WarningDVN
13:29 UTC13:49 UTCTornado 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 Enhanced Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 12:26 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

1.5 hours before the tornado, 22 km from the path. August 11, 2026.

Skew-T log-pSkew-T log-p diagram, Davenport, at 12:00Z on 2026-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 4268 joules per kilogram, CIN -76, lifted condensation level 891 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 2026-08-11The 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 136 square meters per square second, 0 to 6 km bulk shear 38 knots.19395878Sfc1 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
4268 J/kg
Mixed-layer CIN
-76 J/kg
Surface CAPE
3853 J/kg
Mixed-layer LCL
891 m above ground
0-6 km bulk shear
38 kt
0-1 km bulk shear
23 kt
0-1 km storm-relative helicity
136 m²/s²
0-3 km storm-relative helicity
153 m²/s²
Significant tornado parameter
2.1
Supercell composite
9.5
0-3 km lapse rate
4.7 K/km

Open this sounding in Storm Lab

Davenport, (KDVN), 00:00Z

10.5 hours after it, 22 km from the path. August 12, 2026.

Skew-T log-pSkew-T log-p diagram, Davenport, at 00:00Z on 2026-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 3969 joules per kilogram, CIN -90, lifted condensation level 877 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 2026-08-12The 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 121 square meters per square second, 0 to 6 km bulk shear 43 knots.19395878Sfc1 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
3969 J/kg
Mixed-layer CIN
-90 J/kg
Surface CAPE
5532 J/kg
Mixed-layer LCL
877 m above ground
0-6 km bulk shear
43 kt
0-1 km bulk shear
18 kt
0-1 km storm-relative helicity
121 m²/s²
0-3 km storm-relative helicity
214 m²/s²
Significant tornado parameter
3.6
Supercell composite
29.8
0-3 km lapse rate
6.0 K/km

Open this sounding in Storm Lab

The radar

The Quad Cities radar (KDVN), 23 km away, was scanning. The volume nearest the touchdown began at 13:30 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
13:02 UTCTSTM WND DMG1 Ene BaldwinJackson, IALarge branch downed. Time estimated using radar.
13:10 UTCTSTM WND DMGMaquoketaJackson, IAReport of lots of tree damage with lots of branches, including some 1-3 inch, downed and broken or uprooted trees. Time estimated from radar.
13:15 UTCTSTM WND GST 641 Wnw MaquoketaJackson, IAIADOT RWIS.
13:20 UTCTSTM WND GST 681 Wnw MaquoketaJackson, IAIADOT RWIS.
13:25 UTCTSTM WND GST 613 E ElwoodClinton, IAPWS.
13:29 UTCTORNADODewittClinton, IAAn EF0 tornado, with max wind speeds of 85 MPH, caused damage to trees and houses along its half-mile path. The tornado first caused some minor shingle damage to a home before crossing 14th Avenue. Then, damage to a few
13:30 UTCTSTM WND DMGDewittClinton, IAPortion of roofing peeled off a house. Time estimated from radar.
13:51 UTCTSTM WND DMGClintonClinton, IAStorm door on garage was removed from its frame. Lots of tree branches down, including some large.

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

This ground now

The live radar over the trackEvery 2026 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

The other tornadoes of August 11, 2026

28 more have been surveyed in the United States that day, so far.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 117:58 AM EDTEF0Jay, IN0.615
August 117:31 AM CDTEF1Delaware, IA2.4150
August 117:44 AM CDTEF1Delaware, IA1.5100
August 117:45 AM CDTEF1Delaware, IA2.675
August 119:24 AM EDTEF0Clark, OH4.5150
August 119:30 AM EDTEF1Champaign, OH3.6200
August 119:31 AM EDTEF1Clark, OH9.2200
August 119:33 AM EDTEF2Clark, OH3.5400
August 119:44 AM EDTEF1Madison, OH0.8125
August 119:51 AM EDTEF0Madison, OH1.2100
August 1110:05 AM EDTEF0Franklin, OH2.71502
August 1110:05 AM EDTEF1Franklin, OH1.8100
August 1110:08 AM EDTEF1Franklin, OH1.3150
August 1110:14 AM CDTEF0Kendall, IL5.4150
August 1110:20 AM CDTEF0Grundy, IL1.6250
August 1110:23 AM CDTEF0Grundy, IL2.2150
August 1110:37 AM CDTEF1Will, IL1.5150
August 1110:39 AM CDTEF1Will, IL7.6200
August 1110:41 AM CDTEF1Cook, IL to IN22.5300
August 1110:43 AM CDTEF2Will, IL to IN26.2500
August 1110:55 AM CDTEF1Cook, IL3.3300
August 113:13 PM EDTEF1Butler, OH11.3500
August 113:47 PM EDTEF0Clermont, OH5.2200
August 113:49 PM EDTEF0Clermont, OH5.5150
August 113:51 PM EDTEF0Boone, KY2.9150
August 113:56 PM EDTEF0Brown, OH6.4200
August 113:12 PM CDTEF1Piatt, IL22.5800
August 114:16 PM EDTEF1Brown, OH7.1350

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. A survey can be revised, so the rating, the path and the casualties can all still change.

Sources

NWS Damage Assessment Toolkit, the record the survey teams file from the damage, and NOAA Storm Prediction Center storm reports. Neither is the official database for 2026, which SPC publishes in the spring of 2027.