Tornadoes · United States · Iowa · 2026

EF1 tornado, Croton to Franklin, Iowa, March 10, 2026

From Croton to Franklin, this EF1 tornado ran 1.5 miles across Lee County on March 10, 2026, touching down at 9:05 PM CDT and reaching 50 yards wide. It killed nobody.

Preliminary. This is NWS DVN's damage survey, filed in the Damage Assessment Toolkit as SW Donnellson. 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 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.

The survey

Rating, as surveyed
EF1, preliminary
Date
March 10, 2026
Touchdown
9:05 PM CDT (02:05 UTC)
Lifted
9:08 PM CDT (02:08 UTC)
On the ground
3 minutes
Path length
1.5 miles (2.4 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Lee County
Touchdown point
40.624, -91.627
Lift-off point
40.627, -91.599
Highest wind the damage implies
100 mph
Surveyed by
NWS DVN
The office's name for it
SW Donnellson
Survey last edited
March 11, 2026
Record number
None yet. SPC numbers 2026 in the spring of 2027.

What the survey found

An EF1 tornado with peak winds of 95 to 100 mph begun its 1.5 mile long path by downing some tree branches. The tornado increased in strength causing damage to the door of a farm outbuilding along with damage to additional farm out buildings. The tornado continued east along 230th street, causing sporadic tree damage for around 1 mile. The tornado then strengthened even more near 230th street and 160th avenue, where it destroyed two farm outbuildings and snapped numerous tree trunks. This is where the tornado was the strongest. Shortly after crossing 160th street, the tornado weakened and eventually dissipated.

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

What the Weather Service recorded

Numerous severe thunderstorms developed during the afternoon on Tuesday producing hail that ranged in size from penny (0.88) to baseball (2.75) in diameter. There was a total of 10 reports with hail over 2.00 inches in diameter. During the early evening hours, one storm produced three different EF-1 tornadoes in Lee County near Donnellson.

An EF1 tornado with peak winds of 95 to 100 mph began its 1.5 mile long path by downing some tree branches. The tornado increased in strength causing damage to the door of a farm outbuilding along with damage to additional farm out buildings. The tornado continued east along 230th street, causing sporadic tree damage for around 1 mile. The tornado then strengthened even more near 230th street and 160th avenue, where it destroyed two farm outbuildings and snapped numerous tree trunks. This is where the tornado was the strongest. Shortly after crossing 160th street, the tornado weakened and eventually dissipated. The tornado had a max width of 50 yards.

An EF1 tornado with max winds near 90 mph begun its 2.1 mile long path with damage to tree branches. The tornado then caused damage to some fascia on a house and then crossed into Wilson Lake Park where additional trees were downed. Some trees were uprooted with a couple of trees had their trunks snapped. Tree damage became more sporadic as the tornado continued east leading to minor tree damage through the remainder of its path. The max width was 50 yards.

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

The warnings

24 minutes of warning. NWS DVN issued a tornado warning for this county at 01:41 UTC, 24 minutes before the tornado touched down, in force until 02:45 UTC.

The county was under a tornado watch, issued at 20:58 UTC and running to 03:46 UTC.

Issued (UTC)ExpiredProductOffice
20:58 UTC03:46 UTCTornado WatchDVN
01:41 UTC02:45 UTCTornado WarningDVN
02:36 UTC02:59 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 Enhanced Risk, with a 0.05 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 00:34 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), 00:00Z

2.1 hours before the tornado, 145 km from the path. March 11, 2026.

Skew-T log-pSkew-T log-p diagram, Davenport, at 00:00Z on 2026-03-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 343 joules per kilogram, CIN -359, lifted condensation level 771 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 2026-03-11The 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 529 square meters per square second, 0 to 6 km bulk shear 78 knots.1939587897117Sfc1 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
343 J/kg
Mixed-layer CIN
-359 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
771 m above ground
0-6 km bulk shear
78 kt
0-1 km bulk shear
44 kt
0-1 km storm-relative helicity
529 m²/s²
0-3 km storm-relative helicity
725 m²/s²
Significant tornado parameter
0.0
Supercell composite
25.6
0-3 km lapse rate
2.4 K/km

Open this sounding in Storm Lab

The radar

The Quad Cities radar (KDVN), 140 km away, was scanning. The volume nearest the touchdown began at 02:08 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
23:39 UTCHAIL 1WaylandHenry, IAOccurring right now.
23:40 UTCHAIL 11 Ene Fairfield MunicipJefferson, IALasted from 640 to 650 PM. Covered the deck. No wind.
23:45 UTCHAIL 11 Sw PerleeJefferson, IAUp to quarter size hail. Time of the event was estimated using radar.
00:30 UTCHAIL 1.252 E SwedesburgHenry, IADelayed report via social media.
02:05 UTCTSTM WND DMG3 Wsw DonnellsonLee, IACattle shed and feed shed were blown down. Possible tornado.
02:05 UTCTORNADO4 Wsw DonnellsonLee, IAAn EF1 tornado with peak winds of 95 to 100 mph begun its 1.5 mile long path by downing some tree branches. The tornado increased in strength causing damage to the door of a farm outbuilding along with damage to addition
02:10 UTCHAIL 1.52 Sw DonnellsonLee, IA
02:10 UTCHAIL 1.52 Sw DonnellsonLee, IA
02:26 UTCTORNADO2 Sse FranklinLee, IAAn EF1 tornado with max winds near 90 mph begun its 2.1 mile long path with damage to tree branches. The tornado then caused damage to some fascia on a house. It then crossed into Wilson Lake park where additional trees
02:38 UTCTORNADO2 W WeverLee, IAIn coordination with the Denmark, IA Fire Dept, an EF1 tornado with maximum winds of 100 mph and path length of 1.2 miles was determined to have occurred on March 10. Numerous trees were snapped or uprooted, and one powe
02:50 UTCTSTM WND GST 60Burlington Regional AirDes Moines, IAKBRL reported a 52 knot wind gust.

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 March 10, 2026

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

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
March 104:49 PM CDTEF0Livingston, IL1.1175
March 104:57 PM CDTUnratedLivingston, IL0.310
March 106:18 PM CDTUnratedKankakee, IL0.610
March 106:19 PM CDTUnratedKankakee, IL0.560
March 106:21 PM CDTEF3Kankakee, IL to IN35.61,550319
March 106:33 PM CDTEF1Kankakee, IL1.3150
March 106:36 PM CDTUnratedKankakee, IL0.120
March 106:43 PM CDTUnratedKankakee, IL0.120
March 106:51 PM CDTUnratedKankakee, IL1.880
March 107:22 PM CDTEF1Knox, IL5.0100$300
March 107:30 PM CDTEF0Stark, IL6.240
March 107:43 PM CDTEF1Jasper, IN10.59003
March 108:01 PM CDTEF0Marshall, IL12.650
March 108:07 PM CDTEF2Starke, IN15.51,200
March 108:35 PM CDTEF0Starke, IN0.7150
March 109:26 PM CDTEF1Lee, IA2.150
March 109:38 PM CDTEF1Lee, IA1.250
March 1011:52 PM CDTEF1Mason, IL5.6200
March 1012:06 AM CDTEF1Mason, IL10.250
March 1012:30 AM CDTEF2McCurtain, OK2.52401

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.