F1 tornado, Swayzee to Fairmount, Indiana, June 11, 1998

1. F040 to 72 mph

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

2. F173 to 112 mphthis tornado

   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.

Rating

F1

Date

June 11, 1998

Touchdown

7:41 PM EST (00:41 UTC)

Path length

17.0 miles (27.4 km)

Path width

500 yards (457 m)

Deaths

0

Injuries

0

Property damage

$2.0 million

Counties

Madison and Grant counties

Touchdown point

40.280, -85.830

Lift-off point

40.380, -85.620

Record number

477

Synoptic and mesoscale conditions for June 11, 1998...Morning sfc and upper air analysis revealed a potent upper short wave trough across North Dakota with an intensifying area of sfc low pressure across southwest Kansas. An unseasonably strong 140 knot jet streak was ejecting out of this trough across Kansas with the left front exit region progged into central Indiana after 18Z. Increasing moisture convergence and theta-e advection along the northward lifting warmfront was seen as 850 mb winds were forecast to increase to 55 knots. By 21Z, the sfc low had moved into eastern Iowa and deepened to 994 mb. The prestorm enviornment was characterized by moderate to extreme instability (LI values -7 to -9 and CAPE values in excess of 2000 J/kg) with temperatures in the lower 80s and dewpoints in the low/mid 70s. This combined with a dry punch at 700mb and deep layer shear along the warm front, where storm relative helicity values increased to 400 M2/S2, lay the foundation for an outbreak of damaging tornadoes across Indiana.

Supercell produced tornado touching down near Elwood which then tracked NE to just north of Summitville before traversing into SC Grant County before dissipating near Fowlerton. Along its track in northern Madison County this tornado destroyed approximately 9 buildings and damaged about 10 others. Nearly all these buildings were on farms as the tornado passed through farm country before crops emerged.

THIS TORNADO WAS A CONTINUATION OF THE GREENTOWN TORNADO IN HOWARD COUNTY. THE TORNADO WAS WEAKENING AS IT CROSSED INTO GRANT COUNTY BUT CAUSED EXTENSIVE TREE DAMAGE ALONG ITS PATH AND SEVERLY DAMAGED SEVERAL HOMES IN SWAYZEE. MANY OF THE HOMES SUFFERED DAMAGE FROM UPROOTED TREES FALLING ON THEM. MANY TREES AND POWER LINES WERE REPORTED DOWN FROM THIS SERIES OF STORMS. IN ADDITION...VERY HEAVY RAIN CAUSED FLASH FLOODING ACROSS THE COUNTY WITH MANY COUNTY ROADS WASHED OUT OR UNDER WATER.

THIS TORNADO TRACK WAS A CONTINUATION OF THE TORNADO WHICH BEGAN NEAR THE TOWN OF ELWOOD IN MADISON COUNTY. THE TORNADO WAS WEAKENING AS IT CROSSED INTO GRANT COUNTY BUT CAUSED EXTENSIVE DAMAGE TO SEVERAL FARMS. ONE FARMSTEAD SUFFERED A DESTROYED BARN AND AN OVERTURNED JUNK BUS. ANOTHER FARMSTEAD HAD A VERY LARGE METAL OUTBUILDING DESTROYED AND 3 LARGE SILOS WERE BLOWN INTO THE FARM HOUSE WHICH SUFFERED MAJOR DAMAGE. ANOTHER FARM LOST MOST OF ITS OUTBUILDINGS WITH THE ROOF OF THE HOUSE DAMAGED. ANOTHER FARM NEAR FAIRMOUNT SUFFERED SEVERE DAMAGE WITH 2 BARNS DESTROYED AND THE HOUSE LOST ITS ROOF.MANY TREES AND OUTBUILDINGS IN FOWLERTON WERE DAMAGED WERE THE TORNADO FINALLY LIFTED.

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

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.

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 Storm Prediction Center had this point in a Slight Risk. The outlook in force was issued at 10:53 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 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.

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

16 more were confirmed in the United States that day.

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.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.