Tornadoes · United States · Iowa · 2021

Unrated tornado, Farnhamville to Gowrie, Iowa, July 14, 2021

From Farnhamville to Gowrie, this Unrated tornado ran 0.3 miles across Webster County on July 14, 2021, touching down at 4:46 PM CDT and reaching 30 yards wide. It killed nobody.

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 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. 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 record

Rating
Unrated
Date
July 14, 2021
Touchdown
4:46 PM CDT (21:46 UTC)
Lifted
4:47 PM CDT (21:47 UTC)
On the ground
1 minutes
Path length
0.3 miles (0.5 km)
Path width
30 yards (27 m)
Deaths
0
Injuries
0
Crop damage
$500
County
Webster County
Touchdown point
42.295, -94.352
Lift-off point
42.295, -94.346
Record number
2107141546-01

What the Weather Service recorded

A surface low pressure system was centered over Kansas and Nebraska with attendant warm front draped across north central Iowa. This was bisected by an outflow boundary from morning convection across western Iowa. As morning activity exited the are the atmosphere quickly recovered steep low and mid level lapse rates exceeded 8 C/km with 0-6 km shear over 40 knots. Near the remnant outflow boundary 0-1 km SRH exceeded 150 m2/s2. Storms developed along this boundary and moved east along the warm front, spawning a number of tornadoes across the state. In fact, this is in the top 5 for tornadoes occurring in a single day for the state of Iowa since reliable records began in the 1980s. By evening convection congealed into an MCS, bringing heavy rain to portions of the state. A line of training storms set up north of the Des Moines metro, resulting in localized flash flooding.

Brief tornado observed by storm chasers with path determined through use of high resolution satellite imagery. Path was entirely in agricultural fields.

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

The warnings

17 minutes of warning. NWS DMX issued a tornado warning for this county at 21:29 UTC, 17 minutes before the tornado touched down, in force until 22:00 UTC.

The county was under a tornado watch, issued at 19:35 UTC and running to 00:50 UTC.

Issued (UTC)ExpiredProductOffice
19:35 UTC00:50 UTCTornado WatchDMX
21:04 UTC21:10 UTCTornado WarningDMX
21:29 UTC22:00 UTCTornado WarningDMX
23:42 UTC00:18 UTCTornado WarningDMX

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. The outlook in force was issued at 19:48 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), 12:00Z

9.8 hours before the tornado, 200 km from the path. July 14, 2021.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 2021-07-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 967 joules per kilogram, CIN -125, lifted condensation level 1201 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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, Omaha, NE at 12:00Z on 2021-07-14The 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 35 square meters per square second, 0 to 6 km bulk shear 43 knots.193958Sfc1 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
967 J/kg
Mixed-layer CIN
-125 J/kg
Surface CAPE
2147 J/kg
Mixed-layer LCL
1201 m above ground
0-6 km bulk shear
43 kt
0-1 km bulk shear
32 kt
0-1 km storm-relative helicity
35 m²/s²
0-3 km storm-relative helicity
-7 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.1
0-3 km lapse rate
5.7 K/km

Open this sounding in Storm Lab

Omaha, NE (KOAX), 00:00Z

2.2 hours after it, 200 km from the path. July 15, 2021.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 2021-07-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 938 joules per kilogram, CIN -33, lifted condensation level 1401 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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, Omaha, NE at 00:00Z on 2021-07-15The 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 48 square meters per square second, 0 to 6 km bulk shear 26 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
938 J/kg
Mixed-layer CIN
-33 J/kg
Surface CAPE
3380 J/kg
Mixed-layer LCL
1401 m above ground
0-6 km bulk shear
26 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
48 m²/s²
0-3 km storm-relative helicity
128 m²/s²
Significant tornado parameter
0.1
Supercell composite
3.1
0-3 km lapse rate
6.8 K/km

Open this sounding in Storm Lab

The surface observations

Fort Dodge (FOD), 31 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
19:50 UTC150° 5 kt1014.2
19:55 UTC140° 9 kt1013.9
19:56 UTC7769140° 9 kt1013.9
20:00 UTC130° 5 kt1013.9
20:05 UTC140° 8 kt1013.9
20:10 UTC130° 4 kt1014.2
20:15 UTC170° 5 kt1013.9
20:20 UTC130° 5 kt1013.5
20:25 UTC150° 5 kt1013.5
20:30 UTC140° 4 kt1013.5
20:35 UTC160° 4 kt1013.5
20:40 UTC160° 5 kt1013.2
20:45 UTC130° 4 kt1013.2
20:50 UTC160° 5 kt1013.2
20:55 UTC160° 4 kt1012.9
20:56 UTC8072180° 4 kt1012.9
21:00 UTC180° 4 kt1012.9
21:05 UTC160° 5 kt1012.9
21:10 UTC190° 5 kt1012.9
21:20 UTC180° 5 kt1012.9
21:25 UTC180° 5 kt1012.9
21:30 UTC170° 5 kt1012.9
21:35 UTC180° 9 kt1012.9-RA
21:36 UTC78.871.6180° 10 kt1012.9VCTS -RA
21:40 UTC170° 10 kt1012.5RA
21:45 UTC190° 9 kt1012.5-RA
21:50 UTC190° 8 kt1012.5-RA
21:51 UTC7773.4190° 8 kt1012.5-RA
21:55 UTC180° 9 kt1012.9-RA
21:56 UTC7774180° 10 kt1012.9VCTS -RA
22:00 UTC180° 9 kt1012.5-RA
22:05 UTC190° 5 kt1012.5-RA
22:10 UTC190° 5 kt1012.5-RA
22:15 UTC190° 7 kt1012.5-RA
22:20 UTC200° 7 kt1012.5
22:25 UTC210° 9 kt1012.5
22:26 UTC75.269.8210° 8 kt1012.5
22:30 UTC210° 8 kt1012.5
22:35 UTC210° 8 kt1012.2
22:40 UTC210° 7 kt1012.2
22:45 UTC240° 5 kt1012.5
22:50 UTC240° 5 kt1012.2
22:55 UTC230° 4 kt1012.2-RA
22:56 UTC7469240° 4 kt1012.2-RA
23:00 UTC260° 5 kt1012.5-RA
23:05 UTC270° 4 kt1012.2-RA
23:10 UTC270° 5 kt1012.5-RA
23:15 UTC290° 5 kt1012.5-RA
23:20 UTC310° 5 kt1012.5-RA
23:25 UTC310° 5 kt1012.9-RA
23:30 UTC340° 8 kt1012.5-RA
23:32 UTC73.469.8340° 7 kt1012.5VCTS -RA
23:35 UTC330° 7 kt1012.9-RA
23:40 UTC340° 5 kt1012.9-RA
23:45 UTC350° 5 kt1012.5-RA

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Des Moines radar (KDMX), 81 km away, was scanning. The volume nearest the touchdown began at 21:45 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
21:01 UTCTORNADO1 Ene Lake CityCalhoun, IAIOWA STATE PATROL REPORTS CONSIDERABLE DAMAGE TO A HOUSEY. TIME ESTIMATED.
21:01 UTCTORNADOLake CityCalhoun, IAIOWA STATE PATROL REPORTS TREES DOWN IN LAKE CITY. TIME ESTIMATED.
21:01 UTCTORNADOLake CityCalhoun, IARELAYED BY IOWA STATE PATROL.
21:01 UTCTORNADOLake CityCalhoun, IADAMAGE ON THE SOUTH SIDE OF LAKE CITY. TREES DOWN AND POWER LINES DOWN.
21:06 UTCTORNADO3 Ene StratfordHamilton, IATORNADO TOUCHED DOWN AND THEN LIFTED. MAY BE CYCLING WITH A FURTHER TOUCHDOWN.
21:09 UTCTORNADO3 Ene StratfordHamilton, IAMULTI-VORTEX TORNADO.
21:20 UTCTORNADO5 W Story CityStory, IA
21:21 UTCTORNADO2 Nne StanhopeHamilton, IATORNADO ON THE GROUND NEAR 330TH STREET AND KANTO AVENUE NORTHEAST OF STANHOPE.
21:23 UTCTORNADO5 Ese StanhopeHamilton, IALOCATION APPROXIMATE. TORNADO CYCLED UP AND WAS ON GROUND AT THE TIME OF THIS REPORT. REPORT RELAYED BY EMA.
21:25 UTCTORNADO2 N StanhopeHamilton, IAROPE TORNADO JUST TOUCHED DOWN AGAIN.
21:30 UTCTORNADO4 Wnw JewellHamilton, IATORNADO REPORTED WEST OF JEWELL.
21:33 UTCTORNADO2 N JewellHamilton, IADEBRIS REPORTED TORNADO NEAR HIGHWAY 69.
21:33 UTCTORNADO2 W JewellHamilton, IAREPORTED BY SHERIFFS OFFICE. TORNADO WAS HEADING EAST.
21:37 UTCTORNADO2 N JewellHamilton, IALAW ENFORCEMENT REPORTS A TORNADO AT 310TH ST AND HWY 69 NORTH OF JEWELL. TORNADO WENT UP BRIEFLY BUT TOUCHED BACK DOWN AND HAS DEBRIS. IT IS HEADING EAST.
21:40 UTCTORNADO1 Ne JewellHamilton, IATRAINED SPOTTER REPORTED A TORNADO STILL ON THE GROUND ABOUT A MILE NORTHEAST OF JEWELL. SOME DAMAGE SEEN BUT UNKNOWN WHAT WAS HIT. SPOTTER CONFIRMED IT DID GO NORTH OF TOWN.
21:46 UTCTORNADO1 Nw GowrieWebster, IADNR LAW ENFORCEMENT OFFICER REPORTS A TORNADO ALONG 340TH ST.
22:20 UTCTORNADO1 N Sac CitySac, IAVERY BRIEF SKINNY ROPE TORNADO. NO DAMAGE SEEN. REPORT VIA SOCIAL MEDIA.
22:46 UTCFUNNEL CLOUD1 Sw LyttonSac, IAREPORT VIA SOCIAL MEDIA.

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

This ground now

The live radar over the trackEvery 2021 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

The other tornadoes of July 14, 2021

25 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
July 143:52 PM CDTEF3Calhoun, IA10.8505$2.5 million
July 144:05 PM CDTEF0Hamilton, IA8.850$2,000
July 144:21 PM CDTEF1Hamilton, IA8.9160$10,000
July 144:57 PM CDTUnratedButler, IA1.250
July 145:11 PM CDTUnratedSac, IA0.625
July 145:16 PM CDTEF2Butler, IA12.9630$1.3 million
July 145:34 PM CDTEF1Floyd, IA12.060$60,000
July 145:35 PM CDTUnratedSac, IA0.830
July 145:52 PM CDTEF0Cerro Gordo, IA5.1225$10,000
July 146:12 PM CDTEF0Bremer, IA2.5150$1,000
July 145:15 PM MDTUnratedEmery, UT0.110
July 146:43 PM CDTEF0Buchanan, IA3.230$275,000
July 147:05 PM CDTEF1Tama, IA5.7590$25,000
July 147:10 PM CDTUnratedBuchanan, IA0.110
July 147:36 PM CDTUnratedBenton, IA0.110
July 147:50 PM CDTEF1Delaware, IA1.440
July 147:54 PM CDTEF1Delaware, IA1.130
July 147:56 PM CDTUnratedBenton, IA0.110
July 148:07 PM CDTUnratedBenton, IA0.110
July 148:50 PM CDTUnratedLinn, IA0.110
July 148:52 PM CDTUnratedLinn, IA0.110
July 149:40 PM CDTUnratedDelaware, IA0.410
July 149:44 PM CDTEF1Jones, IA1.840
July 1410:02 PM CDTEF1Jones, IA8.030
July 1410:30 PM CDTEF1Jones, IA3.130

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.