Tornadoes · United States · Iowa · 2026
EF1 tornado, Kossuth County, Iowa, May 17, 2026
This EF1 tornado ran 0.7 miles across Kossuth County on May 17, 2026, touching down at 9:29 PM CDT and reaching 30 yards wide. It killed nobody.
Preliminary. This is NWS DMX's damage survey, filed in the Damage Assessment Toolkit as Lone Rock. 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.
EF065 to 85 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mphthis tornado
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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
- May 17, 2026
- Touchdown
- 9:29 PM CDT (02:29 UTC)
- Lifted
- 9:30 PM CDT (02:30 UTC)
- On the ground
- 1 minutes
- Path length
- 0.7 miles (1.2 km)
- Path width
- 30 yards (27 m)
- Deaths
- 0
- Injuries
- 0
- County
- Kossuth County
- Touchdown point
- 43.211, -94.332
- Lift-off point
- 43.221, -94.324
- Highest wind the damage implies
- 100 mph
- Surveyed by
- NWS DMX
- The office's name for it
- Lone Rock
- Survey last edited
- May 20, 2026
- Record number
- None yet. SPC numbers 2026 in the spring of 2027.
The damage survey
9 damage points were recorded along this path by NWS DMX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 100 mph.
- post office roof removed and flipped to the north. be8ck wapps collapsed inward.
Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.
The warnings
21 minutes of warning. NWS DMX issued a tornado warning for this county at 02:08 UTC, 21 minutes before the tornado touched down, in force until 03:00 UTC.
The county was under a tornado watch, issued at 23:13 UTC and running to 04:04 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 23:13 UTC | 04:04 UTC | Tornado Watch | DMX |
| 02:02 UTC | 02:45 UTC | Severe Thunderstorm Warning | DMX |
| 02:08 UTC | 03:00 UTC | Tornado Warning | DMX |
| 02:28 UTC | 03:30 UTC | Severe Thunderstorm Warning | DMX |
| 02:30 UTC | 03:15 UTC | Tornado Warning | DMX |
| 02:35 UTC | 03:15 UTC | Tornado Warning | DMX |
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 0.10 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 01:07 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.
Minneapolis, MN (KMPX), 00:00Z
2.5 hours before the tornado, 191 km from the path. May 18, 2026.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -8890 J/kg
- Surface CAPE
- 0 J/kg
- Mixed-layer LCL
- 1101 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km bulk shear
- 14 kt
- 0-1 km storm-relative helicity
- 154 m²/s²
- 0-3 km storm-relative helicity
- 237 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 5.1 K/km
Minneapolis, MN (KMPX), 12:00Z
9.5 hours after it, 191 km from the path. May 18, 2026.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -7988 J/kg
- Surface CAPE
- 0 J/kg
- Mixed-layer LCL
- 882 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- 149 m²/s²
- 0-3 km storm-relative helicity
- 175 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 3.4 K/km
The surface observations
Algona (AXA), 16 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 00:15 UTC | 78.8 | 68 | 170° 20 kt | 1001.4 | ||
| 00:35 UTC | 77 | 68 | 170° 17 kt | 24 | 1001 | |
| 00:55 UTC | 77 | 68 | 160° 16 kt | 1001 | ||
| 01:15 UTC | 77 | 68 | 160° 18 kt | 1000.7 | ||
| 01:35 UTC | 77 | 69.8 | 160° 14 kt | 21 | 1000.7 | |
| 01:55 UTC | 77 | 69.8 | 160° 17 kt | 1000.3 | ||
| 02:15 UTC | 75.2 | 69.8 | 150° 16 kt | 23 | 1000.3 | |
| 02:35 UTC | 62.6 | 62.6 | 240° 26 kt | 45 | 1004.7 | |
| 02:55 UTC | 60.8 | 60.8 | 270° 27 kt | 32 | 1004.7 | BR |
| 03:15 UTC | 60.8 | 60.8 | 270° 18 kt | 1004.7 | BR | |
| 03:35 UTC | 62.6 | 62.6 | 300° 11 kt | 1004.7 | BR | |
| 03:55 UTC | 62.6 | 62.6 | 300° 6 kt | 13 | 1004.7 | BR |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Des Moines radar (KDMX), 172 km away, was scanning. The volume nearest the touchdown began at 02:30 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) | Report | Where | County | Remark |
|---|---|---|---|---|
| 02:05 UTC | TORNADO | 2 Sse Havelock | Pocahontas, IA | Between Pocahontas and Havelock. |
| 02:08 UTC | TORNADO | 2 Nw Terril | Dickinson, IA | Viewed on social media. |
| 02:08 UTC | TORNADO | 2 Nw Terril | Dickinson, IA | Viewed on social media. |
| 02:12 UTC | TSTM WND DMG | 4 W West Bend | Palo Alto, IA | Daily CoCoRaHS observer notes from IA-PA-5 stated there was damage to a machine shed 1 mile ESE of their location, which is the location of this report. Time estimated from radar. |
| 02:14 UTC | TORNADO | Graettinger | Palo Alto, IA | Reports of power pole and tree damage in town. Time estimated by radar. |
| 02:23 UTC | TSTM WND DMG | 1 N Estherville | Emmet, IA | 2-3 inch diameter limbs down. Time estimated via radar. |
| 02:28 UTC | TORNADO | 3 Ssw Armstrong | Emmet, IA | Confirmed tornado estimated via webcam. |
| 02:33 UTC | TSTM WND DMG | Algona | Kossuth, IA | Delayed report - received photo on social media of large tree limb on home. |
| 02:33 UTC | TSTM WND DMG | Lone Rock | Kossuth, IA | Tree uprooted near Lone Rock. Delayed report from broadcast media, time estimated by radar. |
| 02:38 UTC | TORNADO | 2 S Wesley | Kossuth, IA | Confirmed tornado via Emergency Management. |
| 02:39 UTC | TSTM WND DMG | Algona | Kossuth, IA | Downed tree limb on home. Time estimated via radar. |
| 02:41 UTC | TSTM WND GST 82 | 2 Wnw Gruver | Emmet, IA | ASOS station KEST Estherville Airport. |
| 02:42 UTC | TSTM WND DMG | 4 Wnw Ledyard | Kossuth, IA | Couple of trees down. Time estimated via radar. |
| 02:59 UTC | TORNADO | 4 N Crystal Lake | Winnebago, IA | Reports of power line sparking/flashing. |
| 03:10 UTC | TSTM WND GST 62 | 5 Nw Thompson | Winnebago, IA | |
| 03:11 UTC | TSTM WND GST 67 | 6 Ne Ledyard | Kossuth, IA |
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 May 17, 2026
46 more have been surveyed in the United States that day, so far.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| May 17 | 3:17 PM EDT | EF0 | Lee, FL | 0.1 | 25 | |||
| May 17 | 3:25 PM EDT | EF0 | Lee, FL | 2.1 | 150 | |||
| May 17 | 3:35 PM EDT | EF0 | Lee, FL | 0.5 | 50 | |||
| May 17 | 4:05 PM CDT | Unrated | Turner, SD | 0.7 | 0 | |||
| May 17 | 5:04 PM CDT | EF3 | Howard, NE | 6.1 | 350 | |||
| May 17 | 5:23 PM CDT | EF0 | Merrick, NE | 1.3 | 30 | |||
| May 17 | 5:58 PM CDT | Unrated | Nobles, MN | 1.3 | 25 | |||
| May 17 | 6:15 PM CDT | Unrated | Nobles, MN | 0.6 | 20 | |||
| May 17 | 6:42 PM CDT | EF1 | Thayer, NE | 4.3 | 200 | $10 | ||
| May 17 | 7:11 PM CDT | EF0 | Ida, IA | 0.5 | 60 | |||
| May 17 | 7:12 PM CDT | Unrated | Martin, MN | 0.3 | 0 | |||
| May 17 | 7:19 PM CDT | EF1 | Thurston, NE | 1.9 | 300 | |||
| May 17 | 7:31 PM CDT | EF0 | Woodbury, IA | 2.5 | 75 | |||
| May 17 | 7:37 PM CDT | EF1 | Woodbury, IA | 3.9 | 100 | |||
| May 17 | 7:55 PM CDT | EF1 | Saunders, NE | 0.8 | 40 | |||
| May 17 | 8:07 PM CDT | Unrated | Plymouth, IA | 0.7 | 0 | |||
| May 17 | 8:10 PM CDT | Unrated | Cherokee, IA | 0.4 | 0 | |||
| May 17 | 8:11 PM CDT | Unrated | Cherokee, IA | 0.9 | 0 | |||
| May 17 | 8:15 PM CDT | Unrated | Cherokee, IA | 0.8 | 0 | |||
| May 17 | 8:25 PM CDT | Unrated | Cherokee, IA | 0.9 | 0 | |||
| May 17 | 8:31 PM CDT | Unrated | Clay, IA | 1.2 | 0 | |||
| May 17 | 8:42 PM CDT | Unrated | Buena Vista, IA | 2.2 | 75 | |||
| May 17 | 8:45 PM CDT | EF1 | Cass, NE | 0.8 | 100 | |||
| May 17 | 8:48 PM CDT | Unrated | Clay, IA | 0.9 | 20 | |||
| May 17 | 8:53 PM CDT | Unrated | Clay, IA | 4.0 | 75 | |||
| May 17 | 9:01 PM CDT | EF1 | Calhoun, IA | 4.2 | 50 | |||
| May 17 | 9:03 PM CDT | EF1 | Palo Alto, IA | 3.5 | 25 | |||
| May 17 | 9:05 PM CDT | EF1 | Pocahontas, IA | 1.1 | 25 | |||
| May 17 | 9:06 PM CDT | EF0 | Clay, IA | 1.2 | 30 | |||
| May 17 | 9:08 PM CDT | Unrated | Dickinson, IA | 0.6 | 25 | |||
| May 17 | 9:10 PM CDT | EF1 | Palo Alto, IA | 3.7 | 0 | |||
| May 17 | 9:10 PM CDT | Unrated | Dickinson, IA | 1.5 | 45 | |||
| May 17 | 9:10 PM CDT | EF1 | Calhoun, IA | 0.2 | 30 | |||
| May 17 | 9:12 PM CDT | Unrated | Emmet, IA | 1.3 | 30 | |||
| May 17 | 9:17 PM CDT | EF0 | Palo Alto, IA | 0.8 | 25 | |||
| May 17 | 9:19 PM CDT | EF0 | Palo Alto, IA | 2.7 | 25 | |||
| May 17 | 9:20 PM CDT | EF0 | Palo Alto, IA | 1.1 | 20 | |||
| May 17 | 9:24 PM CDT | EF0 | Webster, IA | 4.7 | 50 | |||
| May 17 | 9:41 PM CDT | EF1 | Kossuth, IA | 10.2 | 0 | |||
| May 17 | 10:07 PM CDT | EF1 | Cerro Gordo, IA | 0.2 | 40 | |||
| May 17 | 10:10 PM CDT | EF1 | Worth, IA | 9.1 | 0 | |||
| May 17 | 10:13 PM CDT | EF1 | Cerro Gordo, IA | 7.0 | 40 | |||
| May 17 | 10:14 PM CDT | EF1 | Freeborn, MN | 1.2 | 0 | |||
| May 17 | 10:15 PM CDT | Unrated | Cerro Gordo, IA | 2.4 | 0 | |||
| May 17 | 10:18 PM CDT | Unrated | Cerro Gordo, IA | 2.6 | 0 | |||
| May 17 | 10:27 PM CDT | EF1 | Freeborn, MN | 0.4 | 0 |
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.