Tornadoes · United States · Iowa · 2020
Unrated tornado, Gladbrook to Garwin, Iowa, August 10, 2020
From Gladbrook to Garwin, this Unrated tornado ran 1.5 miles across Tama County on August 10, 2020, touching down at 12:01 PM CDT and reaching 40 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.
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 record
- Rating
- Unrated
- Date
- August 10, 2020
- Touchdown
- 12:01 PM CDT (17:01 UTC)
- Lifted
- 12:02 PM CDT (17:02 UTC)
- On the ground
- 1 minutes
- Path length
- 1.5 miles (2.4 km)
- Path width
- 40 yards (37 m)
- Deaths
- 0
- Injuries
- 0
- Crop damage
- $1,000
- County
- Tama County
- Touchdown point
- 42.160, -92.621
- Lift-off point
- 42.145, -92.600
- Record number
- 2008101101-01
What the Weather Service recorded
Basic Summary: A cluster of storms in northeast Nebraska and southeast South Dakota developed into the destructive derecho that raced eastward across large portions of Iowa, northern Illinois, southern Wisconsin, northern Indiana, and southern Michigan during the morning and afternoon of August 10th. The strongest winds were experienced in central and east-central Iowa where 100+ mph winds were observed. Some of the strongest winds were in an area from roughly Marshalltown, IA eastward along the Highway 30 corridor to the Mississippi River, where estimated winds exceeded 120+ mph and approached 140 mph. A number of QLCS tornadoes were also experienced within the Highway 30 corridor. One of the most remarkable aspects of the derecho was the duration of severe winds, with many areas experiencing at least periodic, if not persistent, severe level (58+ mph) winds over a roughly 30 minute time frame. As the derecho moved eastward out of Iowa, it continued to expand, but weakened from its peak strength. Winds continued to exceed severe criteria (58+ mph) in Illinois, Wisconsin, Indiana, and Michigan and began to produce additional QLCS tornadoes across northern Illinois before fading out across northern Indiana and southern Michigan.||In the wake of the derecho, damage was substantial in many areas, rural and urban. Many agriculture fields, mainly corn, were flattened within the swaths of strongest winds. Initial estimates suggest at least 850,000 acres of partial or complete crop loss occurred from this event. Within urban and wooded areas extensive tree and structure damage was seen, including complete roof failure in a few instances. At its peak, total estimated customers without power exceeded 1.4 million across the affected states. In total, early estimates on losses (agriculture, infrastructure, private property) have exceeded $7.5 billion across the states affected. ||Environment: Broadly speaking, it was a ripe day for thunderstorms across the affected area with MUCAPE values often exceeding 3500-4000 J/kg by the mid morning hours concurrent with mid-upper level short wave support, and indications that any cold pool development would be strong (difference between cold pool and ambient air) and potentially long lived. For detailed environmental analysis, including soundings, please view the various local NWS office event review pages: NWS Des Moines, NWS Quad Cities, NWS Chicago, NWS Milwaukee, NWS Central Illinois, NWS Northern Indiana, or NWS Indianapolis.||Additional Details: Numerous injuries occurred during the derecho and in the aftermath during cleanup, including 4 direct and indirect deaths of which 3 occurred in Iowa (two in Poweshiek County and one in Linn County) and 1 in Indiana (Fort Wayne).||Disclaimer: The August 10, 2020 derecho resulted in widespread high-end damage across large portions of central and southern Iowa. Given the size and scope of the event and understanding that final damage and loss estimates (agriculture, infrastructure, and private property) will take months to complete, the NWS is not able to estimate the monetary impact at this time. Values may be added as more data becomes from various sources in future months.
Tornado associated with QLCS derecho first observed via high resolution satellite imagery. Path was also overflown by UAS confirming convegent path of debris. No damage indicators were impacted, hence the EFU designation.
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 13:56 UTC and running to 19:00 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 13:56 UTC | 19:00 UTC | Severe Thunderstorm Watch | DMX |
| 16:19 UTC | 17:00 UTC | Severe Thunderstorm Warning | DMX |
| 16:47 UTC | 17:45 UTC | Severe Thunderstorm Warning | DMX |
| 16:52 UTC | 17:30 UTC | Severe Thunderstorm Warning | DMX |
| 17:13 UTC | 17:47 UTC | Severe Thunderstorm Warning | DMX |
| 17:28 UTC | 18:00 UTC | Severe Thunderstorm 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 Moderate Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 15:57 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.
What forecasters said that day
The local office's own words before the tornado touched down, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Des Moines, IA wrote its last area forecast discussion before the tornado touched down at Aug 10, 9:30 AM CDT, 2 hours 31 minutes earlier.
Area forecast discussion, Aug 10, 9:30 AM CDT, 2 hours 31 minutes before
Area Forecast Discussion National Weather Service Des Moines IA 930 AM CDT Mon Aug 10 2020 .UPDATE... Issued at 929 AM CDT Mon Aug 10 2020 Line of severe convection moving into west-central Iowa continues to intensify this morning. Plenty of instability out of ahead of this line and judging by the previous wind reports, there is a well established cold pool. Downdraft CAPE ranges from 1000-1500 J/kg with effective shear 30-40 knots in the vicinity of the convection. Further east however, the 0-6km shear is currently not conducive for sustainable strong storms as it is barely 25 knots as far east as Interstate 35. The outflow from this storm has been producing severe wind gusts in the southwest part of the state and appears the outflow remains connected with the main convection in Crawford County. Expecting the Des Moines Metro to get impacted by this line b/t 11 AM to 12 PM and potentially with severe winds. && .DISCUSSION.../Today through Sunday/ Issued at 245 AM CDT Mon Aug 10 2020 We are anticipating another active morning across portions of the forecast area as an approaching shortwave trough and associated surface front trigger convective development. As of 07z radar returns were quite isolated with small convective complexes noted in northeast Nebraska and near the Twin Cities. Hi-res models initiate more thunderstorm activity in the next few hours as deeper kinematic ascent overspreads the area. Favored corridor this morning continues to be northern Iowa, although convective evolution remains in question especially given the poor performance of the hi-res model suite last night. Sluggish progression of the upper wave keeps some degree of kinematic and thermal support for ascent over the area through much of the day, so expecting additional showers and storms along and behind a southerly sagging cold front. Hi-res models vary from isolated to widespread precip, so potential rainfall coverage and amounts are tough to pinpoint. Ample surface instability builds for a few strong to severe storms along the front later this afternoon and evening, mainly south of I-80. The corridor of stronger winds aloft lags behind the frontal boundary and limits deep layer shear, but should still be strong enough to support some organized updrafts capable of large hail and strong winds. It is worth noting that a faster frontal progression would push the threat south of the state border, but that hinges on the extent morning convection augments the cold front. Precip chances slowly wane across southern Iowa Monday night, giving way to a mainly dry Tuesday as a surface high pressure tracks through the state. Forecast is somewhat muddled over mid to late week. Zonal flow aloft eventually becomes southwesterly as a large trough drops into the northern Rockies. Models show multiple weak shortwaves within the mean flow crossing the region, but provide little agreement on timing/location. Favored areas of ascent and surface convergence are also rather nebulous, which makes it difficult to improve on the broad brushed low chance PoPs in the latest NBM output. Ensemble data continues to cluster highest precip chances around Thursday, but confidence in any sort of widespread precip event is low at this time. High temperatures remain seasonal in the 80s through most of the forecast period. && .AVIATION.../For the 12Z TAFS through 12Z Tuesday morning/ Issued at 617 AM CDT Mon Aug 10 2020 MVFR cigs and tsra associated with a cold front passage are the main forecast challenge through the current TAF period. MVFR cigs currently stretch from KFOD to KMCW, ahead of tsra activity moving out of SD. This is expected to impact terminals in north central Iowa by mid to late morning. Confidence decreases further south toward KDSM, but model guidance suggests tsra holds off until late morning or afternoon. VFR conditions expected to prevail across the area by late this evening into the overnight hours. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && UPDATE...Podrazik DISCUSSION...Martin AVIATION...Martin
Hazardous weather outlook, Aug 10, 9:02 AM CDT, 2 hours 59 minutes before
Hazardous Weather Outlook National Weather Service Des Moines IA 902 AM CDT Mon Aug 10 2020 IAZ023>028-033>039-044>050-057>062-070>075-084>086-111415- Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun- Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene- Boone-Story-Marshall-Tama-Audubon-Guthrie-Dallas-Polk-Jasper- Poweshiek-Cass-Adair-Madison-Warren-Marion-Mahaska-Lucas-Monroe- Wapello- 902 AM CDT Mon Aug 10 2020 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...Today and tonight Severe thunderstorms are expected this morning and afternoon. The storms are likely to be severe with damaging winds. A few storms may also produce tornadoes along with some hail and brief heavy rainfall. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Periodic thunderstorms chances continue though the second half of the week, however at this time the severe threat is uncertain. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed today. IAZ004>007-015>017-111415- Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo- 902 AM CDT Mon Aug 10 2020 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...Today and tonight Thunderstorms are forecast today as a cool front moves across the state. A few storms could be severe with damaging winds and some hail the main threats. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Periodic thunderstorms chances continue though the second half of the week, however at this time the severe threat is uncertain. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed today. IAZ081>083-092>097-111415- Adams-Union-Clarke-Taylor-Ringgold-Decatur-Wayne-Appanoose-Davis- 902 AM CDT Mon Aug 10 2020 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...Today and tonight Thunderstorms are forecast today as a cool front moves across the state. A few storms could be severe with damaging winds and some hail the main threats. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Periodic thunderstorms chances continue though the second half of the week, however at this time the severe threat is uncertain. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed today. REV
In the hours before
Local storm report, Aug 10, 11:47 AM CDT, 14 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1147 AM CDT MON AUG 10 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1055 AM TSTM WND GST 5 WSW CUMMING 41.45NLocal storm report, Aug 10, 11:48 AM CDT, 13 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1148 AM CDT MON AUG 10 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1116 AM TSTM WND DMG CARLISLE 41.50N 93.49W
08/10/2020 WARREN IALocal storm report, Aug 10, 11:51 AM CDT, 10 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1151 AM CDT MON AUG 10 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1047 AM TSTM WND GST 1 WSW WEST DES MOINES 41.56N 93.78W
08/10/2020 E70 MPH POLK IA TRAINED SPOTTER
MILLS CIVIC AND I35; 70 MPH WINDS. SIGN AND
TREE DAMAGE. WINDS OF 55 TO 70 LASTED NEARLY
20 MINUTES DURING THE SURGE.
&&
REVLocal storm report, Aug 10, 11:58 AM CDT, 3 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1158 AM CDT MON AUG 10 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1157 AM TSTM WND GST LEIGHTON 41.34N 92.78W
08/10/2020 M75 MPH MAHASKA IA MESONET
REPORTED AT LEIGHTON, IA. PWS.
&&
FOWLELocal storm report, Aug 10, 11:59 AM CDT, 2 minutes before
PRELIMINARY LOCAL STORM REPORT NATIONAL WEATHER SERVICE DES MOINES IA 1159 AM CDT MON AUG 10 2020
Local storm report, Aug 10, 12:01 PM CDT, 0 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1201 PM CDT MON AUG 10 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1158 AM TSTM WND DMG STATE CENTER 42.02N 93.17W
08/10/2020 MARSHALL IA EMERGENCY MNGR
SIGNIFICANT DAMAGE IN STATE CENTER. NUMEROUS
CARS BLOWN OFF US30 AND FLIPPED.
&&
FOWLEThe 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), 12:00Z
5.0 hours before the tornado, 184 km from the path. August 10, 2020.
- Mixed-layer CAPE
- 1683 J/kg
- Mixed-layer CIN
- -223 J/kg
- Surface CAPE
- 2014 J/kg
- Mixed-layer LCL
- 894 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km bulk shear
- 18 kt
- 0-1 km storm-relative helicity
- 80 m²/s²
- 0-3 km storm-relative helicity
- 96 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
- 0-3 km lapse rate
- 3.8 K/km
Davenport, (KDVN), 00:00Z
7.0 hours after it, 184 km from the path. August 11, 2020.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -3409 J/kg
- Surface CAPE
- 75 J/kg
- Mixed-layer LCL
- 1429 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km bulk shear
- 9 kt
- 0-1 km storm-relative helicity
- -60 m²/s²
- 0-3 km storm-relative helicity
- -33 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 4.4 K/km
The radar
The Des Moines radar (KDMX), 103 km away, was scanning. The volume nearest the touchdown began at 16:58 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 |
|---|---|---|---|---|
| 16:15 UTC | TSTM WND DMG | Zearing | Story, IA | TREE AND BIN DAMAGE. TIME ESTIMATED. |
| 16:30 UTC | TORNADO | 4 Nne Melbourne | Marshall, IA | BRIEF QLCS TORNADO ON LEADING EDGE OF CONVECTION. PATH FOUND VIA HIGH RESOLUTION SATELLITE IMAGERY. THE TORNADO IMPACTED NO DAMAGE INDICATORS, HENCE THE EFU RATING. DELAYED REPORT. |
| 16:36 UTC | TORNADO | 4 Wnw Albion | Marshall, IA | BRIEF TORNADO CAPTURED FROM POST EVENT UAS SURVEY. STAYED IN CROPLAND WITH NO IMPACTS TO DAMAGE INDICATORS, HENCE THE EFU RATING. DELAYED REPORT. |
| 16:38 UTC | TSTM WND GST 77 | 3 S Hubbard | Hardin, IA | MESONET STATION FW1669 HUBBARD. |
| 16:39 UTC | TORNADO | 2 Sse Albion | Marshall, IA | TORNADO INITIALLY FOUND FROM HIGH RESOLUTION SATELLITE IMAGERY AND CONFIRMED VIA UAS OVERFLIGHT. DAMAGE WAS DONE TO CROP AND TREES. SOME MINOR DAMAGE TO HOUSING STRUCTURES AS WELL, BUT MOSTLY SUPERFICIAL. DELAYED REPORT. |
| 16:43 UTC | TSTM WND GST 70 | Hubbard | Hardin, IA | NUMEROUS LARGE TREES DOWN. WINDS ESTIMATED AT 70 MPH. |
| 16:43 UTC | TSTM WND GST 91 | 3 Sw Marshalltown | Marshall, IA | MESONET STATION RMTI4 MARSHALLTOWN (US 30) - IA DOT RWIS. |
| 16:47 UTC | TSTM WND DMG | 2 Wsw Union | Hardin, IA | DAMAGE TO BARNS AND ROOFS. |
| 16:50 UTC | TSTM WND GST 99 | 4 E Albion | Marshall, IA | ASOS STATION KMIW MARSHALLTOWN AIRPORT. PEAK GUST THUS FAR. |
| 16:51 UTC | TSTM WND DMG | 2 S Marshalltown | Marshall, IA | SEVERAL LARGE SECTIONS OF ROOFS BLOWN OFF BUILDINGS ALONG OLD HIGHWAY 30 ON SOUTH PART OF MARSHALLTOWN. |
| 16:51 UTC | TSTM WND GST 95 | 2 S Marshalltown | Marshall, IA | ESTIMATED WINDS OF 90 TO 100 MPH. |
| 16:52 UTC | TSTM WND GST 106 | 2 Wnw Le Grand | Marshall, IA | PERSONAL WEATHER STATION KIAMARSH15. |
| 16:55 UTC | TSTM WND GST 70 | Toledo | Tama, IA | 70 MPH PLUS WIND GUST IN TOLEDO. TREE STRUCK OFFICE. |
| 16:58 UTC | TSTM WND DMG | State Center | Marshall, IA | SIGNIFICANT DAMAGE IN STATE CENTER. NUMEROUS CARS BLOWN OFF US30 AND FLIPPED. |
| 16:58 UTC | TSTM WND GST 75 | 2 Sw Conrad | Marshall, IA | |
| 17:00 UTC | TSTM WND DMG | 1 S Marshalltown | Marshall, IA | SIGNIFICANT TREE AND STRUCTURAL DAMAGE. EXACT TIME UNKNOWN. |
| 17:00 UTC | TSTM WND GST 90 | 3 S Chelsea | Tama, IA | |
| 17:01 UTC | TSTM WND DMG | 3 N Toledo | Tama, IA | 60X90 FOOT MACHINE SHED COMPLETELY DEMOLISHED. NEIGHBORS (EMPTY) GRAIN BINS WERE BLOWN ACROSS HIGHWAY 63. SEVERAL LARGE TREES SNAPPED AND/OR UPROOTED. MEASURED WIND GUST OF 78 MPH BEFORE WEATHER STATION GAVE OUT. |
| 17:01 UTC | TORNADO | 5 Ese Gladbrook | Tama, IA | TORNADO ASSOCIATED WITH QLCS DERECHO FIRST OBSERVED VIA HIGH RESOLUTION SATELLITE IMAGERY. PATH WAS ALSO OVERFLOWN BY UAS CONFIRMING CONVEGENT PATH OF DEBRIS. NO DAMAGE INDICATORS WERE IMPACTED, HENCE THE EFU DESIGNATION |
| 17:10 UTC | TSTM WND DMG | 3 Ssw Grinnell | Poweshiek, IA | SEMI BLOWN OVER ON I-80 JUST WEST OF THE GRINNELL INTERCHANGE. |
| 17:15 UTC | TSTM WND DMG | Reinbeck | Grundy, IA | TREES DOWN ALL OVER TOWN ON THE ROADS. ESTIMATED WIND SPEEDS 70 MPH. TIME ESTIMATED. |
| 17:15 UTC | TSTM WND GST 70 | Belle Plaine | Benton, IA | MULTIPLE SPOTTER REPORTS OF 70+ MPH WINDS FROM BELLE PLAINE TO LUZERNE. |
| 17:19 UTC | TSTM WND GST 60 | 1 S Grundy Center | Grundy, IA | ALONG WITH PEA SIZED HAIL. |
| 17:25 UTC | TSTM WND GST 90 | Blairstown | Benton, IA | WINDS IN EXCESS OF 90 MPH WITH MAJOR DAMAGE REPORTED IN TOWN. |
| 17:25 UTC | TSTM WND GST 120 | 4 Nne Van Horne | Benton, IA | DELAYED REPORT. ANTENNA MOUNTED ON A TOWER AT 340 FEET ABOVE GROUND WAS SNAPPED OFF. ANTENNA WAS RATED TO WITHSTAND 125 MPH WINDS. |
| 17:28 UTC | TSTM WND DMG | Keystone | Benton, IA | WIDESPREAD DAMAGE ACROSS SOUTHERN BENTON COUNTY, FROM KEYSTONE, TO VAN HORNE AND THE ATKINS AREA. NUMEROUS HOUSES, OUTBUILDINGS, GRAIN BINS AND TREES DAMAGED OR DESTROYED. TIME ESTIMATED. |
| 17:28 UTC | TSTM WND GST 70 | 6 Nne Van Horne | Benton, IA | |
| 17:30 UTC | TSTM WND DMG | Elberon | Tama, IA | COOP GRAIN BINS BLOWN IN AND SEVERELY DAMAGED. WIDESPREAD CROP DAMAGE ACROSS TAMA COUNTY. DELAYED REPORT AND TIME ESTIMATED BY RADAR. |
| 17:30 UTC | TSTM WND DMG | 5 S Vinton | Benton, IA | LARGE GRAIN BINS DESTROYED AND BLOWN AROUND YARD. ONE IS UP AGAINST THE HOUSE, WHILE THE OTHER IS IN A BUNCH OF TREES. SOME SIDING DAMAGE TO THEIR HOUSE ALSO. |
| 17:44 UTC | TSTM WND GST 70 | Vinton | Benton, IA | REPORTED A MEASURED GUST OF 70 MPH. |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2020 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are
The other tornadoes of August 10, 2020
26 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| August 10 | 11:30 AM CDT | Unrated | Marshall, IA | 1.0 | 50 | |||
| August 10 | 11:36 AM CDT | Unrated | Marshall, IA | 0.4 | 50 | |||
| August 10 | 11:39 AM CDT | EF1 | Marshall, IA | 2.9 | 100 | $20,000 | ||
| August 10 | 12:31 PM CDT | Unrated | Linn, IA | 0.9 | 40 | |||
| August 10 | 12:32 PM CDT | EF0 | Grant, WI | 0.6 | 50 | $15,000 | ||
| August 10 | 2:12 PM CDT | EF0 | Stephenson, IL | 4.6 | 50 | |||
| August 10 | 2:37 PM CDT | EF0 | Winnebago, IL | 1.6 | 50 | |||
| August 10 | 2:47 PM CDT | EF1 | Winnebago, IL | 9.2 | 300 | |||
| August 10 | 2:50 PM CDT | EF0 | DeKalb, IL | 6.3 | 40 | |||
| August 10 | 2:59 PM CDT | EF1 | LaSalle, IL | 0.9 | 150 | |||
| August 10 | 3:05 PM CDT | EF1 | McHenry, IL | 5.7 | 200 | |||
| August 10 | 3:12 PM CDT | EF1 | Kane, IL | 1.2 | 40 | |||
| August 10 | 3:15 PM CDT | EF1 | Kendall, IL | 14.4 | 250 | |||
| August 10 | 3:35 PM CDT | EF1 | DuPage, IL | 0.4 | 100 | |||
| August 10 | 3:38 PM CDT | EF0 | Walworth, WI | 3.3 | 50 | $12,000 | ||
| August 10 | 3:39 PM CDT | EF1 | DuPage, IL | 2.1 | 200 | |||
| August 10 | 3:41 PM CDT | EF1 | Lake, IL to WI | 6.3 | 150 | $250,000 | ||
| August 10 | 3:54 PM CDT | EF1 | Cook, IL | 4.8 | 300 | |||
| August 10 | 3:57 PM CDT | EF0 | Cook, IL | 2.0 | 350 | |||
| August 10 | 3:59 PM CDT | EF1 | Cook, IL | 3.2 | 300 | |||
| August 10 | 4:04 PM CDT | EF0 | Kankakee, IL | 1.5 | 150 | |||
| August 10 | 5:05 PM EDT | EF1 | Washington, NY | 1.5 | 100 | $75,000 | ||
| August 10 | 4:15 PM CDT | EF0 | Newton, IN | 0.9 | 40 | |||
| August 10 | 6:32 PM EDT | EF1 | Saint Joseph, IN | 2.4 | 100 | |||
| August 10 | 6:55 PM EDT | EF1 | Kosciusko, IN | 3.1 | 100 | |||
| August 10 | 7:43 PM EDT | EF0 | Kosciusko, IN | 0.2 | 50 |
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.