Tornadoes · United States · Illinois · 2020
EF0 tornado, DeKalb County, Illinois, August 10, 2020
This EF0 tornado ran 6.3 miles across DeKalb County on August 10, 2020, touching down at 2:50 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 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
- August 10, 2020
- Touchdown
- 2:50 PM CDT (19:50 UTC)
- Lifted
- 2:57 PM CDT (19:57 UTC)
- On the ground
- 7 minutes
- Path length
- 6.3 miles (10.1 km)
- Path width
- 40 yards (37 m)
- Deaths
- 0
- Injuries
- 0
- County
- DeKalb County
- Touchdown point
- 42.096, -88.927
- Lift-off point
- 42.124, -88.810
- Record number
- 2008101350-01
The damage survey
27 damage points were recorded along this path by NWS LOT, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 112 mph.
- Tornado Crossed Spring Brook, shingles off nearby apartments to NE. Extensive tree damage, large trees.
- Tree damage at Trainer and Burlwood, no shingle or home damage seen
- some shingles removed, extensive tree damage
- shingles and some siding missing.
Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.
The warnings
No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.
The county was under a severe thunderstorm watch, issued at 16:28 UTC and running to 21:25 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 16:28 UTC | 21:25 UTC | Severe Thunderstorm Watch | LOT |
| 19:03 UTC | 20:30 UTC | Severe Thunderstorm Warning | LOT |
| 20:11 UTC | 20:21 UTC | Tornado Warning | LOT |
| 21:23 UTC | 22:53 UTC | High Wind Warning | LOT |
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.
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.
Davenport, (KDVN), 12:00Z
7.8 hours before the tornado, 146 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
4.2 hours after it, 146 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 Chicago radar (KLOT), 86 km away, was scanning. The volume nearest the touchdown began at 19:48 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 |
|---|---|---|---|---|
| 19:15 UTC | TSTM WND GST 100 | Forreston | Ogle, IL | *** 5 INJ *** UPDATES PREVIOUS TSTM WIND DMG REPORT FROM FORRESTON. SEVERAL TRAILERS WERE DAMAGED OR DESTROYED. SIGNIFICANT DAMAGE WAS DONE TO A METAL BUILDING NEAR THE BP GAS STATION WITH ASSOCIATED DEBRIS BLOWN TOWARD |
| 19:18 UTC | TSTM WND DMG | Forreston | Ogle, IL | *** 5 INJ *** UPDATES PREVIOUS TSTM WND DMG REPORT FROM FORRESTON. MULTIPLE TRAILERS BLOWN OVER BY WIND AND NUMEROUS TREES DOWN IN FORRESTON. RELAYED BY EMERGENCY MANAGER. NUMBER OF INJURIES REPORTED BY BROADCAST MEDIA. |
| 19:18 UTC | TSTM WND DMG | Forreston | Ogle, IL | MULTIPLE TRAILERS BLOWN OVER BY WIND AND NUMEROUS TREES DOWN IN FORRESTON. RELAYED BY EMERGENCY MANAGER. |
| 19:39 UTC | TSTM WND GST 92 | 4 Ssw Dixon | Lee, IL | PRIVATE WEATHER STATION OBSERVED 92 MPH WIND GUST JUST SOUTH OF DIXON AT 2:39 PM. 20-30 MINUTES OF WINDS GUSTING MORE THAN 50MPH. |
| 19:40 UTC | TSTM WND DMG | 2 Nw Hillcrest | Ogle, IL | LARGE TREE LIMB DOWN. TIME ESTIMATED BY RADAR. |
| 19:40 UTC | TSTM WND DMG | 2 Se Rockford | Winnebago, IL | LARGE LIMB DOWN. TIME ESTIMATED BY RADAR. |
| 19:45 UTC | TSTM WND DMG | 1 Ese Rockford | Winnebago, IL | 1 FOOT DIAMETER BRANCH DOWNED. WINDS ESTIMATED AT 60 MPH. TIME ESTIMATED BY RADAR. |
| 19:45 UTC | TSTM WND DMG | 3 Se Loves Park | Winnebago, IL | IN ROCKFORD, LOTS OF DOWNED TREES, POWER LINES AND POLES, AND FENCES NORTHEAST OF THE AREA FROM NEAR THE NORTH ALPINE AND GUILFORD INTERSECTION THRU SHAW WOODS TO THE MULFORD RD AND SPRINGBROOK ROAD INTERSECTION AND ACRO |
| 19:45 UTC | TSTM WND DMG | Rockford | Winnebago, IL | TRAINED SPOTTER REPORTS WIDESPREAD TREE DAMAGE IN ROCKFORD. MEDIUM TO LARGE BRANCHES AND TREES SNAPPED. |
| 19:46 UTC | TSTM WND DMG | 2 Nne Mendota | La Salle, IL | THUNDERSTORM DOWNED LARGE TREE ON THE PROPERTY OF A MANUFACTURED HOME AND IMPALED A SMALL BRANCH FROM THIS INTO ONE OF THE WALLS. TIME ESTIMATED FROM RADAR. |
| 19:47 UTC | TORNADO | 2 Sw Rockford | Winnebago, IL | A VERY BRIEF TORNADO WITH PEAK WINDS OF 75 MPH AND PATH LENGTH OF 1.5 MILES TOUCHED DOWN NEAR THE INTERSECTION OF PIERPONT AVE AND MONTAGUE ROAD AND CONTINUED NORTHEAST INTO THE SOUTHWEST SIDE OF ROCKFORD. THE TORNADO EN |
| 19:47 UTC | TORNADO | 4 Se Machesney Park | Winnebago, IL | AN EF-1 TORNADO WITH PEAK WINDS OF 100 MPH AND PATH LENGTH OF 9.2 TOUCHED DOWN JUST NORTH OF ROCKFORD COLLEGE AND TRAVELED NORTHEAST INTO CALEDONIA. SIGNIFICANT TREE DAMAGE CONSISTENT WITH EF-1 SPEEDS OCCURED IN A LOCALI |
| 19:48 UTC | TSTM WND DMG | Creston | Ogle, IL | LARGE TREE LIMBS DOWNED. TIME ESTIMATED BY RADAR. |
| 19:50 UTC | TSTM WND DMG | 2 N Kirkland | De Kalb, IL | PHOTOS SHOW TREE DAMAGE AND FLATTENED CROPS ALONG BUCK ROAD NORTH OF KIRKLAND. TIME ESTIMATED BY RADAR. |
| 19:50 UTC | TSTM WND DMG | 3 E Loves Park | Winnebago, IL | LARGE TREES SNAPPED AND LARGE LIMBS DOWN ON THE ROCK VALLEY COLLEGE CAMPUS. TIME ESTIMATED BY RADAR. |
| 19:52 UTC | TSTM WND DMG | 4 Ese Machesney Park | Winnebago, IL | FARM AND FLEET ON EAST RIVERSIDE ROAD IN LOVES PARK LOST A GOOD PORTION OF ITS ROOF. |
| 19:53 UTC | TSTM WND DMG | Kirkland | De Kalb, IL | POWER LINES DOWNED, AND CORN FLATTENED. TIME ESTIMATED BY RADAR. |
| 19:53 UTC | TSTM WND GST 75 | Lee | De Kalb, IL | ESTIMATED 70 TO 80 MPH WINDS AND DIME SIZE HAIL. |
| 19:53 UTC | HAIL 1 | 4 Nnw Cherry Valley | Winnebago, IL | |
| 19:54 UTC | TORNADO | 2 Nne Kirkland | De Kalb, IL | DRONE FOOTAGE SHOWS A NARROW SWATH OF CORN FLATTENED IN A CONVERGENT PATTERN. THIS BRIEF EF-0 TORNADO CROSSED BUCK ROAD AND PEARL STREET BEFORE LIFTING IN A FIELD EAST OF MYELLE ROAD. |
| 19:55 UTC | TSTM WND DMG | 4 Sw Caledonia | Winnebago, IL | TREE DOWN AND DAMAGE TO A METAL STRUCTURE. TIME ESTIMATED BY RADAR. |
| 19:59 UTC | TSTM WND GST 90 | Somonauk | De Kalb, IL | AN NWS DAMAGE SURVEY FOUND WIDESPREAD TREE DAMAGE WITH A FEW TREES SNAPPED VERY NEAR THEIR BASE. SEVEN LARGE AND NEW UTILITY POLES WERE ALSO SNAPPED ABOUT 10 FEET UP FROM THEIR BASE THREE MILES NORTH OF SOMONAUK. THE DAM |
| 20:00 UTC | TSTM WND DMG | 1 E Rockford | Winnebago, IL | ROCKFORD FIRE CHIEF REPORTS AT LEAST 150 DAMAGED POWER POLES ACROSS THE CITY. |
| 20:00 UTC | HAIL 1 | 1 Wnw Belvidere | Boone, IL | |
| 20:05 UTC | TSTM WND DMG | Dekalb | De Kalb, IL | MULTIPLE TREES AND POWER LINES DOWN. ESTIMATED 60 MPH GUSTS. |
| 20:05 UTC | TORNADO | 3 S Marengo | Mchenry, IL | AN EF-1 TORNADO WITH PEAK WINDS OF 95 MPH AND PATH LENGTH OF 5.7 MILES TOUCHED DOWN ON HARMONY ROAD SOUTHWEST OF I-90 AND CONTINUED NORTHEAST BEFORE LIFTING NEAR DUNHAM ROAD BETWEEN MARENGO AND UNION. MOST DAMAGE WAS CON |
| 20:10 UTC | TSTM WND DMG | Maple Park | Kane, IL | MULTIPLE TREES AND POWER LINES DOWN, INCLUDING 10 AND 20 INCH IN DIAMETER TREES. FENCES ALSO BLOWN DOWN. TIME ESTIMATED BY RADAR. |
| 20:12 UTC | TORNADO | 3 Ssw Virgil | Kane, IL | DRONE FOOTAGE REVEALS A NARROW SWATH OF CORN LIKELY AROUND 40 YARDS ACROSS FLATTENED IN A CONVERGENT PATTERN. IN ADDITION, DAMAGE TO A BARN WAS NOTED, WITH A NEAR COMPLETE REMOVAL OF THE ROOF. THIS DAMAGE IS CONSISTENT W |
| 20:14 UTC | TSTM WND GST 57 | 2 Ese Somonauk | La Salle, IL | PRIVATE WEATHER STATION OBSERVED 57 MPH WIND GUST NEAR LAKE HOLIDAY. WIND GUSTS OVER 50 MPH FOR AT LEAST 15 MINUTES. |
| 20:15 UTC | TSTM WND DMG | 3 E Kaneville | Kane, IL | 8 INCH DIAMETER TREE SNAPPED NEAR IL-47 AND NOTTINGHAM. RELAYED VIA NWS CHAT, TIME ESTIMATED BY RADAR. |
| 20:15 UTC | TSTM WND DMG | 3 Ese Maple Park | Kane, IL | 4 INCH DIAMETER BRANCH DOWNED AND DAMAGE TO TRAFFIC SIGNALS AT IL-38 AND MEREDITH ROAD. TIME ESTIMATED BY RADAR. |
| 20:15 UTC | TSTM WND DMG | Somonauk | De Kalb, IL | TRAINED SPOTTER REPORTS WIDESPREAD TREE AND POWER LINE DAMAGE ACROSS SOMANAUK. TREES UP TO 4-6 DIAMETER SNAPPED AT THE BASE. |
| 20:16 UTC | TSTM WND GST 62 | 1 Wnw Sugar Grove | Kane, IL | AURORA ASOS PEAK GUST. |
| 20:16 UTC | TSTM WND GST 62 | 2 W Sugar Grove | Kane, IL | |
| 20:20 UTC | TSTM WND DMG | 2 W Sugar Grove | Kane, IL | TREE DAMAGE BLOCKING FAYS LANE WEST OF SUGAR GROVE. TIME ESTIMATED BY RADAR. |
| 20:20 UTC | TSTM WND DMG | Aurora | Kane, IL | 10 INCH DIAMETER TREE SNAPPED. TIME ESTIMATED BY RADAR. |
| 20:23 UTC | TSTM WND GST 54 | Rockford Airport | Winnebago, IL | ROCKFORD ASOS PEAK GUST. |
| 20:27 UTC | TSTM WND DMG | 1 Se Wayne | Dupage, IL | TREE DOWN ON ROAD NEAR NANCY LN AND POWIS RD IN WAYNE. |
| 20:29 UTC | TSTM WND DMG | St. Charles | Kane, IL | 14 INCH DIAMETER TREE SPLIT IN HALF. POWER LINES DOWNED. TIME ESTIMATED BY RADAR. |
| 20:30 UTC | TSTM WND DMG | Richmond | Mchenry, IL | TREE OVER 12 INCHES IN DIAMETER SNAPPED. NEAR US-12 AND IL-173. |
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 IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois 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 | 12:01 PM CDT | Unrated | Tama, IA | 1.5 | 40 | |||
| 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 | 2:59 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.