Tornadoes · United States · Indiana · 1998

F0 tornado, DeKalb County, Indiana, May 31, 1998

This F0 tornado ran 0.1 miles across DeKalb County on May 31, 1998, touching down at 12:44 PM EST and reaching 30 yards wide. It killed nobody.

The rating scale

Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. F040 to 72 mphthis tornado

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. F173 to 112 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. F2113 to 157 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. F3158 to 206 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. F4207 to 260 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. F5261 to 318 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
F0
Date
May 31, 1998
Touchdown
12:44 PM EST (17:44 UTC)
Path length
0.1 miles (0.2 km)
Path width
30 yards (27 m)
Deaths
0
Injuries
0
County
DeKalb County
Touchdown point
41.280, -84.920
Lift-off point
41.280, -84.920
Record number
867

The warnings

30 minutes of warning. NWS IWX issued a tornado warning for this county at 17:14 UTC, 30 minutes before the tornado touched down, in force until 18:05 UTC.

Issued (UTC)ExpiredProductOffice
17:14 UTC18:05 UTCTornado WarningIWX
18:05 UTC18:35 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 Slight Risk. The outlook in force was issued at 10:32 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

5.7 hours before the tornado, 202 km from the path. May 31, 1998.

Skew-T log-pSkew-T log-p diagram, Detroit, MI at 12:00Z on 1998-05-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -40858, lifted condensation level 1019 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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 1998-05-31The 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 0 square meters per square second, 0 to 6 km bulk shear 48 knots.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
-40858 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1019 m above ground
0-6 km bulk shear
48 kt
0-1 km bulk shear
46 kt
0-1 km storm-relative helicity
0 m²/s²
0-3 km storm-relative helicity
18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.9 K/km

Open this sounding in Storm Lab

Detroit, MI (KDTX), 00:00Z

6.3 hours after it, 202 km from the path. June 1, 1998.

Skew-T log-pSkew-T log-p diagram, Detroit, MI at 00:00Z on 1998-06-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -2, lifted condensation level 961 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 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 1998-06-01The 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 -68 square meters per square second, 0 to 6 km bulk shear 47 knots.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
-2 J/kg
Surface CAPE
22 J/kg
Mixed-layer LCL
961 m above ground
0-6 km bulk shear
47 kt
0-1 km bulk shear
12 kt
0-1 km storm-relative helicity
-68 m²/s²
0-3 km storm-relative helicity
35 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.3 K/km

Open this sounding in Storm Lab

The surface observations

Defiance (DFI), 42 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
15:53 UTC8469240° 13 kt241002.7
16:53 UTC8669230° 17 kt231002.4
17:53 UTC8465240° 14 kt261001.7
18:33 UTC69.862.6280° 9 kt221003.4+RA
18:39 UTC69.864.4270° 11 kt201003+RA
18:43 UTC69.864.4250° 13 kt201003.4-RA
18:53 UTC7065230° 8 kt1002.7

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

The radar

The Northern Indiana radar (KIWX), 66 km away, was scanning. The volume nearest the touchdown began at 17:45 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.

This ground now

The live radar over the trackEvery 1998 tornado in IndianaEvery tornado in Indiana since 1950Warnings in force in Indiana nowThe forecast where you are

The other tornadoes of May 31, 1998

45 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 311:20 AM CDTF0Marathon, WI0.250$10,000
May 312:20 AM CDTF1Calumet, WI1.480$300,000
May 315:30 AM EDTF0Missaukee, MI0.3100
May 315:35 AM EDTF0Antrim, MI0.130
May 315:50 AM EDTF1Kalkaska, MI7.0100
May 315:55 AM EDTF0Crawford, MI0.130
May 316:25 AM EDTF0Genesee, MI0.130$10,000
May 311:15 PM ESTF0DeKalb, IN0.130
May 313:04 PM EDTF0Putnam, OH0.130
May 313:22 PM CDTF3Saratoga, NY to VT30.597068$71 million
May 314:37 PM EDTF1Albany, NY3.580$30,000
May 314:45 PM EDTF0Delaware, NY3.080$150,000
May 315:05 PM EDTF1Chautauqua, NY2.0302$70,000
May 315:20 PM EDTF1Lycoming, PA0.5440
May 315:30 PM EDTF3Tioga, NY62.020012$2.5 million
May 315:50 PM EDTF2Chenango, NY1.01,500$500,000
May 316:00 PM EDTF0Chenango, NY0.580$140,000
May 316:03 PM EDTF2Hillsborough, NH0.590$30,000
May 316:25 PM EDTF0Otsego, NY0.730$70,000
May 316:30 PM EDTF3Otsego, NY5.08003$800,000
May 317:00 PM EDTF0Luzerne, PA0.240$50,000
May 317:22 PM EDTF2Rensselaer, NY8.0200$180,000
May 317:25 PM EDTF1Clinton, OH0.3100$20,000
May 317:30 PM EDTF1Elk, PA3.0100
May 317:30 PM EDTF0Elk, PA0.5100
May 318:08 PM EDTF2Pike, PA2.0550$200,000
May 318:10 PM EDTF1Cameron, PA5.050
May 318:20 PM EDTF3Pike, PA20.02002$1.0 million
May 318:20 PM EDTF2Pike, PA3.0200$400,000
May 318:20 PM EDTF0Lackawanna, PA0.330$70,000
May 318:20 PM EDTF0Lackawanna, PA0.1100$100,000
May 318:45 PM EDTF1Lycoming, PA7.080
May 318:50 PM EDTF3Somerset, PA13.0880115$4.0 million
May 318:50 PM EDTF0Wayne, PA0.530$50,000
May 319:00 PM EDTF3Berks, PA8.31207$1.4 million
May 319:02 PM EDTF0Lycoming, PA0.550
May 319:15 PM EDTF0Lycoming, PA0.240
May 319:15 PM EDTF1Wyoming, PA0.550$70,000
May 319:30 PM EDTF1Northwest Hills Planning Region, CT0.330$4,000
May 318:35 PM CDTF2Adair, KY1.0100$300,000
May 319:50 PM EDTF0Pike, PA0.330$40,000
May 3110:48 PM EDTF1Bell, KY1.5300$200,000
May 3112:30 AM EDTF2Lancaster, PA7.0880
May 3112:52 AM EDTF1Chester, PA3.0100$300,000
May 311:20 AM EDTF2Philadelphia, PA5.6200$1.8 million

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.