Tornadoes · United States · Iowa · 2012
EF0 tornado, Moneta to Everly, Iowa, May 1, 2012
From Moneta to Everly, this EF0 tornado ran 2.6 miles across Clay County on May 1, 2012, touching down at 9:40 PM CDT and reaching 50 yards wide. It killed nobody, and did $5,000 of property damage.
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 mphthis tornado
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.
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 record
- Rating
- EF0
- Date
- May 1, 2012
- Touchdown
- 9:40 PM CDT (02:40 UTC)
- Lifted
- 9:45 PM CDT (02:45 UTC)
- On the ground
- 5 minutes
- Path length
- 2.6 miles (4.2 km)
- Path width
- 50 yards (46 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $5,000
- County
- Clay County
- Touchdown point
- 43.130, -95.370
- Lift-off point
- 43.120, -95.320
- Record number
- 1205012040-01
What the Weather Service recorded
Thunderstorms produced large hail and damaging winds at numerous locations in northwest Iowa during the evening of May 1st. There was also one report of a tornado.
A tornado damaged several power poles.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
11 minutes of warning. NWS FSD issued a tornado warning for this county at 02:29 UTC, 11 minutes before the tornado touched down, in force until 03:15 UTC.
The county was under a severe thunderstorm watch, issued at 02:18 UTC and running to 05:56 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 20:00 UTC | 02:18 UTC | Tornado Watch | FSD |
| 02:15 UTC | 02:45 UTC | Severe Thunderstorm Warning | FSD |
| 02:18 UTC | 05:56 UTC | Severe Thunderstorm Watch | FSD |
| 02:29 UTC | 03:15 UTC | Tornado Warning | FSD |
| 02:41 UTC | 03:15 UTC | Severe Thunderstorm Warning | FSD |
| 02:44 UTC | 03:15 UTC | Tornado Warning | FSD |
| 03:13 UTC | 03:30 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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 00:58 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
2.7 hours before the tornado, 218 km from the path. May 2, 2012.
- Mixed-layer CAPE
- 1502 J/kg
- Mixed-layer CIN
- -30 J/kg
- Surface CAPE
- 2322 J/kg
- Mixed-layer LCL
- 1477 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 75 m²/s²
- 0-3 km storm-relative helicity
- 122 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 5.2
- 0-3 km lapse rate
- 6.7 K/km
Omaha, NE (KOAX), 12:00Z
9.3 hours after it, 218 km from the path. May 2, 2012.
- Mixed-layer CAPE
- 2537 J/kg
- Mixed-layer CIN
- -61 J/kg
- Surface CAPE
- 436 J/kg
- Mixed-layer LCL
- 500 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km bulk shear
- 10 kt
- 0-1 km storm-relative helicity
- 41 m²/s²
- 0-3 km storm-relative helicity
- 100 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.6
- 0-3 km lapse rate
- 4.2 K/km
The surface observations
Spencer (SPW), 12 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 00:53 UTC | 75 | 62 | 160° 19 kt | 1000.7 | ||
| 01:53 UTC | 73 | 62 | 160° 24 kt | 33 | 999.7 | |
| 02:42 UTC | 71.6 | 62.6 | 170° 22 kt | 32 | 1001 | VCTS -RA |
| 02:53 UTC | 70 | 62 | 310° 22 kt | 31 | 1003.4 | -TSRA |
| 02:56 UTC | 62.6 | 59 | 320° 27 kt | 34 | 1003.4 | TSRA BR |
| 03:00 UTC | 59 | 55.4 | 320° 21 kt | 34 | 1003.4 | +TSRA BR |
| 03:03 UTC | 57.2 | 55.4 | 330° 22 kt | 34 | 1003.7 | +TSRA BR |
| 03:09 UTC | 57.2 | 55.4 | 330° 25 kt | 31 | 1004.1 | +TSRA BR |
| 03:12 UTC | 57.2 | 55.4 | 350° 27 kt | 31 | 1004.1 | +TSRA BR |
| 03:53 UTC | 59 | 57 | 20° 14 kt | 1003.4 | -RA |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Sioux Falls radar (KFSD), 123 km away, was scanning. The volume nearest the touchdown began at 02:39 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 |
|---|---|---|---|---|
| 02:00 UTC | TSTM WND GST 87 | 1 Wsw Orange City | Sioux, IA | MEASURED BY RWIS STATION. |
| 02:15 UTC | TSTM WND GST 74 | 3 Ese Spencer | O'Brien, IA | |
| 02:17 UTC | TSTM WND GST 80 | 4 Nnw Sanborn | O'Brien, IA | DAMAGE TO SEVERAL OUTBUILDINGS TO THREE FARMSTEADS. WINDS ESTIMATED BETWEEN 70 AND 85 MPH. |
| 02:20 UTC | TSTM WND GST 60 | Nnw Sanborn | O'Brien, IA | NUMEROUS 1 TO 3 INCH DIAMETER TREE BRANCHES BLOWN DOWN. |
| 02:35 UTC | TSTM WND GST 70 | 1 S Ocheyedan | Osceola, IA | |
| 02:40 UTC | TORNADO | 3 S Everly | Clay, IA | SEVERAL POWER POLES LEANING ALONG 130TH AVENUE SOUTH OF EVERLY. |
| 02:40 UTC | TORNADO | 3 Sw Everly | Clay, IA | |
| 02:44 UTC | TSTM WND GST 0 | 5 N Sutherland | O'Brien, IA | 70-80 MPH WIND GUST |
| 02:44 UTC | TSTM WND GST 70 | 5 N Sutherland | O'Brien, IA | |
| 02:44 UTC | TSTM WND GST 75 | 5 N Sutherland | O'Brien, IA | 70-80 MPH WIND GUST |
| 02:55 UTC | TSTM WND GST 65 | Se Spencer | Clay, IA | NUMEROUS TREES DOWN AND SOME WINDOWS BLOWN OUT OF BUILDINGS. |
| 02:56 UTC | TSTM WND GST 60 | 3 N Royal | Clay, IA | |
| 03:00 UTC | HEAVY RAIN 0 | 12 E Rock Rapids | Lyon, IA | 2.92 INCHES OF RAINFALL |
| 03:00 UTC | HEAVY RAIN 2.92 | 12 E Rock Rapids | Lyon, IA | 2.92 INCHES OF RAIN |
| 03:06 UTC | TSTM WND GST 71 | Spencer | Clay, IA | MEASURED BY RWIS. |
| 03:18 UTC | TSTM WND GST 65 | 3 Ne Dickens | Clay, IA | DAMAGE TO ROOF. |
| 03:20 UTC | TSTM WND GST 70 | 5 Ne Ruthven | Palo Alto, IA | HORIZONTAL RAIN AND NUMEROUS 6 INCHE TREE BRANCHES DOWN. |
| 03:22 UTC | HAIL 0.88 | 5 W Estherville | Dickinson, IA |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2012 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are
The other tornadoes of May 1, 2012
16 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| May 1 | 1:30 AM CDT | EF2 | Craig, OK | 1.0 | 150 | 1 | $250,000 | |
| May 1 | 2:33 PM EDT | EF0 | Clay, IN | 0.1 | 50 | $3,000 | ||
| May 1 | 4:45 PM EDT | EF0 | Trimble, KY | 1.9 | 15 | $25,000 | ||
| May 1 | 3:59 PM CDT | EF0 | Piatt, IL | 0.1 | 10 | |||
| May 1 | 4:06 PM CDT | EF1 | Champaign, IL | 8.1 | 75 | $25,000 | ||
| May 1 | 5:28 PM EDT | EF1 | Franklin, IN | 1.3 | 100 | $250,000 | ||
| May 1 | 4:40 PM CDT | EF0 | Champaign, IL | 0.1 | 20 | |||
| May 1 | 4:48 PM CDT | EF0 | Pope, MN | 0.1 | 50 | |||
| May 1 | 4:56 PM CDT | EF0 | Stearns, MN | 0.9 | 75 | |||
| May 1 | 5:05 PM CDT | EF0 | Stearns, MN | 2.1 | 75 | $100,000 | ||
| May 1 | 5:18 PM CDT | EF0 | Vermilion, IL | 0.5 | 30 | $8,000 | ||
| May 1 | 6:20 PM EDT | EF0 | Warren, OH | 0.0 | 10 | $5,000 | ||
| May 1 | 6:24 PM EDT | EF0 | Warren, OH | 0.0 | 50 | $10,000 | ||
| May 1 | 5:40 PM CDT | EF0 | Wright, MN | 0.0 | 25 | |||
| May 1 | 6:57 PM EDT | EF0 | Fountain, IN | 0.1 | 50 | |||
| May 1 | 7:36 PM EDT | EF1 | Montgomery, IN | 0.5 | 150 | $48,000 |
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.