Tornadoes · United States · Iowa · 2026
Unrated tornado, Archer, Iowa, April 13, 2026
This Unrated tornado ran 0.9 miles across O'Brien County on April 13, 2026, touching down at 6:30 PM CDT and reaching 25 yards wide. It killed nobody.
Preliminary. This is NWS FSD's damage survey, filed in the Damage Assessment Toolkit as 20260413. 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 mph
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.
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 survey
- Rating, as surveyed
- Unrated, preliminary
- Date
- April 13, 2026
- Touchdown
- 6:30 PM CDT (23:30 UTC)
- Lifted
- 6:35 PM CDT (23:35 UTC)
- On the ground
- 5 minutes
- Path length
- 0.9 miles (1.4 km)
- Path width
- 25 yards (23 m)
- Deaths
- 0
- Injuries
- 0
- County
- O'Brien County
- Touchdown point
- 43.138, -95.712
- Lift-off point
- 43.147, -95.725
- Surveyed by
- NWS FSD
- The office's name for it
- 20260413
- Survey last edited
- April 14, 2026
- Record number
- None yet. SPC numbers 2026 in the spring of 2027.
What the survey found
Locations estimated by video and first hand account.
Written by NWS FSD in the NWS Damage Assessment Toolkit. A survey is revised as better evidence arrives.
The damage survey
2 damage points were recorded along this path by NWS FSD, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EFU.
- Estimated starting point based on first hand account and radar.
- Estimated ending point based on first hand account and radar.
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
At late afternoon, considerable moisture focused near a strong warm front from low pressure across northeastern Nebraska through northwest Iowa. Climatologically significant mid-level lapse rates produced a strong capping inversion which gradually weakened north of the warm front. Storms initiated with effective deep-layer shear from 40 to 50 knots and quickly became severe hail producers north of the warm front across southeast South Dakota into southwest Minnesota during the late afternoon, with additional storms developing in proximity to the surface wave across northwest Iowa. One of these latter storms produced two weak tornadoes across northwest Iowa.
An eyewitness observed a tornado develop 2 miles northeast of Archer south of 350th Street in an open field. The tornado tracked northwest slowly over the next five minutes through open fields. After crossing Pierce Avenue, the tornado dissipated. There was no known damage, resulting in an EFU rating. The location, track, and a maximum path width of 25 yards was estimated from video.
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.
The county was under a severe thunderstorm watch, issued at 21:41 UTC and running to 02:14 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 21:41 UTC | 02:14 UTC | Severe Thunderstorm Watch | FSD |
| 23:05 UTC | 23:45 UTC | Severe Thunderstorm Warning | FSD |
| 23:45 UTC | 23:58 UTC | Severe Thunderstorm Warning | FSD |
| 23:53 UTC | 00:31 UTC | Severe Thunderstorm Warning | FSD |
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 Slight Risk, with a 0.02 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 19:56 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.
Omaha, NE (KOAX), 00:00Z
0.5 hours after it, 210 km from the path. April 14, 2026.
- Mixed-layer CAPE
- 215 J/kg
- Mixed-layer CIN
- -51 J/kg
- Surface CAPE
- 733 J/kg
- Mixed-layer LCL
- 3086 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- 152 m²/s²
- 0-3 km storm-relative helicity
- 239 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.0
- 0-3 km lapse rate
- 9.0 K/km
The radar
The Sioux Falls radar (KFSD), 96 km away, was scanning. The volume nearest the touchdown began at 23:27 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 |
|---|---|---|---|---|
| 22:37 UTC | HAIL 1.25 | 7 S Remsen | Plymouth, IA | |
| 22:42 UTC | HAIL 2.75 | 5 Ssw Remsen | Plymouth, IA | |
| 22:51 UTC | HAIL 0.5 | Ashton | Osceola, IA | Report from mPING: Half-inch (0.50 in.). |
| 23:08 UTC | HAIL 1.75 | 4 Se Granville | O'Brien, IA | |
| 23:08 UTC | HAIL 1.75 | 4 Se Granville | Obrien, IA | |
| 23:10 UTC | HAIL 1.75 | 4 S Remsen | Plymouth, IA | |
| 23:25 UTC | HAIL 1 | 7 Ene Melvin | Osceola, IA | Spotter report of quarter inch hail with pictures. |
| 23:27 UTC | HAIL 1 | 8 Se Ocheyedan | Osceola, IA | Social media report with a coin for reference. Time estimated by radar. |
| 23:28 UTC | HAIL 1 | Primghar | O'Brien, IA | |
| 23:28 UTC | HAIL 1 | Primghar | Obrien, IA | |
| 23:30 UTC | HAIL 1.75 | 1 S Harris | Osceola, IA | Social media report with picture. Time estimated by radar. |
| 23:30 UTC | TORNADO | 2 Ne Archer | O'Brien, IA | Corrects time of previous tornado report from 2 NE Archer. Start of brief tornado which tracked generally north and northwest for around 5 minutes. Track was through open fields with no visible damage. Location and track |
| 23:32 UTC | HAIL 0.75 | 5 S Lake Park | Dickinson, IA | |
| 23:34 UTC | HAIL 1.75 | 3 Nne Archer | O'Brien, IA | Social media report with picture of estimated hail size. |
| 23:34 UTC | HAIL 1.75 | 3 Nne Archer | Obrien, IA | Social media report with picture of estimated hail size. |
| 23:40 UTC | HAIL 1 | 3 S Sanborn | O'Brien, IA | Report from mPING: Quarter (1.00 in.). |
| 23:40 UTC | HAIL 1 | 3 S Sanborn | Obrien, IA | Report from mPING: Quarter (1.00 in.). |
| 23:40 UTC | HAIL 1.5 | Sanborn | O'Brien, IA | Report from mPING: Ping Pong Ball (1.50 in.). |
| 23:40 UTC | HAIL 1.5 | Sanborn | Obrien, IA | Report from mPING: Ping Pong Ball (1.50 in.). |
| 23:41 UTC | HAIL 1.25 | Sanborn | O'Brien, IA | |
| 23:41 UTC | HAIL 1.25 | Sanborn | Obrien, IA | |
| 23:44 UTC | HAIL 1.5 | Sanborn | O'Brien, IA | |
| 23:44 UTC | HAIL 1.5 | Sanborn | Obrien, IA | |
| 23:53 UTC | HAIL 1 | Melvin | Osceola, IA | |
| 00:20 UTC | HAIL 0.75 | 4 Ese Arnolds Park | Dickinson, IA | |
| 00:24 UTC | HAIL 1 | 2 Nw Peterson | Clay, IA | Breif heavy rain and hail up to the size of quarters. |
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 April 13, 2026
15 more have been surveyed in the United States that day, so far.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| April 13 | 5:38 PM CDT | EF0 | Taylor, WI | 3.5 | 20 | |||
| April 13 | 6:12 PM CDT | Unrated | Watonwan, MN | 0.7 | 25 | |||
| April 13 | 6:15 PM CDT | EF1 | Watonwan, MN | 8.5 | 200 | |||
| April 13 | 6:47 PM CDT | EF2 | Palo Alto, IA | 4.8 | 450 | |||
| April 13 | 6:47 PM CDT | EF1 | Emmet, IA | 0.9 | 40 | |||
| April 13 | 7:02 PM CDT | EF0 | Osage, KS | 0.0 | 0 | |||
| April 13 | 7:15 PM CDT | EF1 | Faribault, MN | 4.5 | 50 | |||
| April 13 | 7:23 PM CDT | EF2 | Franklin, KS | 7.3 | 0 | 3 | ||
| April 13 | 7:49 PM CDT | EF0 | Clay, IA | 1.8 | 50 | |||
| April 13 | 8:00 PM CDT | EF1 | Linn, KS to MO | 23.8 | 0 | 2 | ||
| April 13 | 8:05 PM CDT | EF1 | Freeborn, MN | 2.7 | 140 | |||
| April 13 | 8:09 PM CDT | Unrated | Linn, KS | 0.6 | 0 | |||
| April 13 | 8:18 PM CDT | EF2 | Miami, KS | 3.0 | 250 | 1 | ||
| April 13 | 12:44 AM CDT | EF0 | Dodge, WI | 0.3 | 50 | |||
| April 13 | 12:45 AM CDT | EF1 | Dane, WI | 5.9 | 75 |
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.