F2 tornado, Flora to Clay City, Illinois, April 15, 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 mph

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

3. F2113 to 157 mphthis tornado

   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

F2

Date

April 15, 1998

Touchdown

8:45 PM CDT (01:45 UTC)

Path length

9.5 miles (15.3 km)

Path width

150 yards (137 m)

Deaths

0

Injuries

8

Property damage

$2.1 million

County

Clay County

Touchdown point

38.650, -88.530

Lift-off point

38.700, -88.380

Record number

910

A severe thunderstorm, which originated in eastern Missouri, travelled to the east across southern Illinois. It produced numerous tornadoes. When it moved into our county warning area, it produced two tornadoes over Clay County. The first tornado touched down 3 miles west southwest of Flora. As it travelled to the northeast it destroyed a set of crossing signals along a set of railroad tracks. It moved parallel to the tracks and on the west edge of Flora it blew 60 to 70 cars of a moving CSX freight train off the tracks. No injuries were reported with the train crew or anyone nearby. At this point the tornado was F2 intensity. Most of the tornado track through Flora stayed south of the railroad tracks. In this area most of the structural damage to frame houses was relatively minor with roof/siding damage the most common. A few homes totally lost roofs, garages/storage sheds were destroyed, and one unanchored mobile home was destroyed and landed about 100 feet from its foundation. Three occupants sustained minor injuries. Several vehicles in the area were damaged from falling trees and debris. The tornado briefly lifted and came down again on the east side of town. It damaged or destroyed 40 to 50 condominiums, which was due more to a result of poor construction techniques rather than wind speed. Roof structures did not survive, with the rafters only consisting of 2x4s. The tornado was rated F1 in this area. After hitting the condominium complex, the tornado caused light damage to an industrial park with power poles down and 10 businesses sustaining damage. From there the damage was light, mainly to trees. Two miles northwest of Clay City, the tornado overturned a mobile home before lifting. At about the same time, half a mile to the north of the first tornado, another tornado formed and touched down. It destroyed a mobile home (F2 intensity) and then travelled to the northeast causing spotty damage, mainly to trees. It destroyed a shed 5 miles north of Olney (Richland County) before lifting and dissipating. In total 8 people sustained minor injuries. Damage in Clay County was estimated around $2.2 million and no damage estimate was available for Richland County.

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

23 minutes of warning. NWS ILX issued a tornado warning for this county at 01:22 UTC, 23 minutes before the tornado touched down, in force until 02:15 UTC.

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 High Risk. The outlook in force was issued at 10:56 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 IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

18 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.