Tornadoes · United States · Indiana · 2020

EF1 tornado, Saint Joseph County, Indiana, August 10, 2020

This EF1 tornado ran 2.4 miles across Saint Joseph County on August 10, 2020, touching down at 6:32 PM EDT and reaching 100 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 mphthis tornado

    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. 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
EF1
Date
August 10, 2020
Touchdown
6:32 PM EDT (22:32 UTC)
Lifted
6:37 PM EDT (22:37 UTC)
On the ground
5 minutes
Path length
2.4 miles (3.9 km)
Path width
100 yards (91 m)
Deaths
0
Injuries
0
County
Saint Joseph County
Touchdown point
41.508, -86.122
Lift-off point
41.507, -86.076
Record number
2008101632-01

The damage survey

19 damage points were recorded along this path by NWS IWX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 110 mph.

  • This area of damage appears to be from a microburst, not tornadic.
  • grain bin partially toppled. This area of damage appears to be from a microburst, not tornadic.
  • 12 ft diameter tank lofted over 4 ft wall.
  • tank lofted and deposited into field

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 20:28 UTC and running to 23:30 UTC.

Issued (UTC)ExpiredProductOffice
20:28 UTC23:30 UTCSevere Thunderstorm WatchIWX
21:19 UTC22:30 UTCSevere Thunderstorm WarningIWX
22:24 UTC23:07 UTCSevere Thunderstorm WarningIWX
22:41 UTC22:50 UTCTornado WarningIWX

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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:38 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.

Detroit, MI (KDTX), 12:00Z

10.5 hours before the tornado, 258 km from the path. August 10, 2020.

Skew-T log-pSkew-T log-p diagram, Detroit, MI at 12:00Z on 2020-08-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 350 joules per kilogram, CIN -98, lifted condensation level 1133 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, Detroit, MI at 12:00Z on 2020-08-10The 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 -3 square meters per square second, 0 to 6 km bulk shear 23 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
350 J/kg
Mixed-layer CIN
-98 J/kg
Surface CAPE
156 J/kg
Mixed-layer LCL
1133 m above ground
0-6 km bulk shear
23 kt
0-1 km bulk shear
17 kt
0-1 km storm-relative helicity
-3 m²/s²
0-3 km storm-relative helicity
19 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.6 K/km

Open this sounding in Storm Lab

Detroit, MI (KDTX), 00:00Z

1.5 hours after it, 258 km from the path. August 11, 2020.

Skew-T log-pSkew-T log-p diagram, Detroit, MI at 00:00Z on 2020-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1727 joules per kilogram, CIN -3, lifted condensation level 1196 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 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, Detroit, MI at 00:00Z on 2020-08-11The 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 58 square meters per square second, 0 to 6 km bulk shear 14 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
1727 J/kg
Mixed-layer CIN
-3 J/kg
Surface CAPE
1732 J/kg
Mixed-layer LCL
1196 m above ground
0-6 km bulk shear
14 kt
0-1 km bulk shear
13 kt
0-1 km storm-relative helicity
58 m²/s²
0-3 km storm-relative helicity
71 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.7 K/km

Open this sounding in Storm Lab

The surface observations

Plymouth (C65), 23 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
20:35 UTC8675.2210° 10 kt1012.2
20:55 UTC8675.2210° 11 kt1012.5
21:15 UTC84.275.2170° 6 kt1011.9
21:35 UTC84.275.2190° 7 kt1011.5
21:55 UTC84.275.2190° 7 kt1011.5
22:15 UTC84.275.2200° 7 kt1011.9
22:30 UTC73.466.2290° 21 kt451015.2HZ
22:55 UTC6866.2300° 18 kt271014.6BR
23:15 UTC6866.2310° 16 kt261014.2
23:35 UTC6866.2330° 10 kt151013.5

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

The radar

The Northern Indiana radar (KIWX), 37 km away, was scanning. The volume nearest the touchdown began at 22:32 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
22:10 UTCTSTM WND GST 632 E BremsStarke, IN
22:30 UTCTSTM WND DMG2 N BourbonMarshall, INTREES AND POWER LINES DOWN ALONG WITH PEA SIZED HAIL.
22:30 UTCTSTM WND DMGPlymouthMarshall, INTREES AND POWER LINES DOWN ACROSS PLYMOUTH AREA. TIME ESTIMATED FROM RADAR.
22:30 UTCTSTM WND DMGRochesterFulton, INREPORTS OF TREES DOWN.
22:35 UTCTSTM WND DMG4 E GrangerElkhart, INTREE AND POWER LINE DOWN OVER ROAD. VIA TWITTER.
22:36 UTCTSTM WND DMGOsceolaSt. Joseph, INTREES DOWN.
22:40 UTCTSTM WND DMGMentoneKosciusko, INDELAYED REPORT OF SEVERAL LARGE TREES DOWN IN MENTONE VICINITY INCLUDING A LARGE TREE FALLING ON TOP OF A HOUSE.
22:40 UTCTORNADO3 Sw WakarusaElkhart, INNWS SURVEY CONFIRMED AN EF1 TORNADO ON AUGUST 11TH 2020.
22:40 UTCTORNADO3 Sw WakarusaElkhart, INPHOTOS ON TWITTER SUGGEST POSSIBLE TORNADO DAMAGE. TEAM TO SURVEY ON TUESDAY.
22:44 UTCTSTM WND DMG1 N NappaneeElkhart, INSEVERAL LARGE TREES DOWN IN NAPPANEE. TIME ESTIMATED FROM RADAR.
22:45 UTCTSTM WND DMGMonoquetKosciusko, INNEIGHBORHOOD OF NORTHWEST WOODS HAD THREE TREES DOWNED, AROUND 1 TO 2 FT IN DIAMETER. APPEARED REASONABLY HEALTHY. NUMEROUS SMALL TO MEDIUM SIZED LIMBS DOWN, RANGING FROM 3 TO 8 INCHES IN DIAMETER. ESTIMATED THUNDERSTORM
22:50 UTCTSTM WND DMG1 N OswegoKosciusko, INLARGE TREE DOWN ON THE ROAD. TIME ESTIMATED FROM RADAR.
22:50 UTCTSTM WND DMG1 Ssw LeesburgKosciusko, INLARGE TREE BRANCH WAS DOWN ACROSS SR 15. TREE SHOWS SOME ROT.
22:54 UTCTSTM WND DMG1 Nnw Winona LakeKosciusko, INA NUMBER OF LARGE TREE BRANCHES DOWN. BRANCHES LOOK HEALTHY IN TWITTER PICTURE.
22:54 UTCTSTM WND DMGLeesburgKosciusko, INMULTIPLE LARGE TREE LIMBS DOWN IN LEESBURG. TIME ESTIMATED FROM RADAR.
22:56 UTCTORNADO2 Ne North WebsterKosciusko, INNWS STORM SURVEY CONCLUDED EF-1 TORNADO OCCURRED. TORNADO TRACKED SOUTHEAST TO 1 MILE EAST OF NORTH WEBSTER BEFORE DISSIPATING. TREES WERE SNAPPED WEST OF STATE ROAD 13. A CHURCH SUSTAINED A LOSS OF ROOF COVERING. SOME H
22:57 UTCTSTM WND DMGJames LakeKosciusko, INLARGE TREE DOWN.
22:58 UTCTSTM WND DMG1 N North WebsterKosciusko, INWIDESPREAD TREE DAMAGE AS WELL AS SOME STRUCTURE DAMAGE FROM FALLING TREES IN THE EPWORTH FOREST AREA.
23:05 UTCTSTM WND DMGCromwellNoble, IN
23:05 UTCTSTM WND DMGSouth WhitleyWhitley, INREPORTS OF TREES AND POWER LINES DOWN. TIME ESTIMATED FROM RADAR.
23:07 UTCTSTM WND DMG1 N North WebsterKosciusko, INPOWER LINES DOWN ON NORTH SIDE OF NORTH WEBSTER.

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 IndianaEvery tornado in Indiana since 1950Warnings in force in Indiana nowThe forecast where you are

The other tornadoes of August 10, 2020

26 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 1011:30 AM CDTUnratedMarshall, IA1.050
August 1011:36 AM CDTUnratedMarshall, IA0.450
August 1011:39 AM CDTEF1Marshall, IA2.9100$20,000
August 1012:01 PM CDTUnratedTama, IA1.540
August 1012:31 PM CDTUnratedLinn, IA0.940
August 1012:32 PM CDTEF0Grant, WI0.650$15,000
August 102:12 PM CDTEF0Stephenson, IL4.650
August 102:37 PM CDTEF0Winnebago, IL1.650
August 102:47 PM CDTEF1Winnebago, IL9.2300
August 102:50 PM CDTEF0DeKalb, IL6.340
August 102:59 PM CDTEF1LaSalle, IL0.9150
August 103:05 PM CDTEF1McHenry, IL5.7200
August 103:12 PM CDTEF1Kane, IL1.240
August 103:15 PM CDTEF1Kendall, IL14.4250
August 103:35 PM CDTEF1DuPage, IL0.4100
August 103:38 PM CDTEF0Walworth, WI3.350$12,000
August 103:39 PM CDTEF1DuPage, IL2.1200
August 103:41 PM CDTEF1Lake, IL to WI6.3150$250,000
August 103:54 PM CDTEF1Cook, IL4.8300
August 103:57 PM CDTEF0Cook, IL2.0350
August 103:59 PM CDTEF1Cook, IL3.2300
August 104:04 PM CDTEF0Kankakee, IL1.5150
August 105:05 PM EDTEF1Washington, NY1.5100$75,000
August 104:15 PM CDTEF0Newton, IN0.940
August 106:55 PM EDTEF1Kosciusko, IN3.1100
August 107:43 PM EDTEF0Kosciusko, IN0.250

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.