Tornadoes · United States · Wisconsin · 1998
F2 tornado, Benton to Calamine, Wisconsin, May 15, 1998
From Benton to Calamine, this F2 tornado ran 20.0 miles across Lafayette County on May 15, 1998, touching down at 7:45 PM CDT and reaching 150 yards wide. It killed nobody and injured 11, and did $1.7 million of property damage.
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.
F040 to 72 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
F173 to 112 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
F4207 to 260 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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
- F2
- Date
- May 15, 1998
- Touchdown
- 7:45 PM CDT (00:45 UTC)
- Path length
- 20.0 miles (32.2 km)
- Path width
- 150 yards (137 m)
- Deaths
- 0
- Injuries
- 11
- Property damage
- $1.7 million
- County
- Lafayette County
- Touchdown point
- 42.550, -90.400
- Lift-off point
- 42.800, -90.200
- Record number
- 223
What the Weather Service recorded
After the F2 tornado tore through Lafayette county a series of severe thunderstorms pummeled southcentral and southeast Wisconsin with numerous reports of tree limb damage and trees downed, which in turn downed a few power lines. The highest reported wind gust was 65 mph near Reedsburg (Sauk Co.). Other notable damage included roofs and doors ripped off of buildings in Mayville (Dodge Co.) and a deck ripped off a house in Ripon (Fond du Lac Co.) where several cars where also damaged by felled trees.
A supercell thunderstorm, after dropping a couple tornadoes in northeast Iowa, eventually moved northeast into Lafayette county, creating another tornado. This tornado touched down just southwest of Benton and hopped/skipped northeast for 20 miles. It caused moderate to severe damage to 40 different farms and their outbuildings, and homes. Numerous power lines were downed. Eleven people were injured: 2 children near Cuba city, 3 children southwest of Truman, and 6 adults in a vehicle on Highway 81 south of Benton. Several farm fields sustained damage.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
17 minutes of warning. NWS MKX issued a tornado warning for this county at 00:28 UTC, 17 minutes before the tornado touched down, in force until 01:30 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 00:28 UTC | 01:30 UTC | Tornado Warning | MKX |
| 01:25 UTC | 02:10 UTC | Tornado Warning | MKX |
| 02:11 UTC | 02:45 UTC | Severe Thunderstorm Warning | MKX |
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. The outlook in force was issued at 11:01 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 surface observations
Mineral Point (MRJ), 24 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 22:55 UTC | 78.8 | 69.8 | 170° 15 kt | 24 | 1005.8 | HZ |
| 23:15 UTC | 78.8 | 69.8 | 160° 20 kt | 28 | 1004.7 | HZ |
| 23:35 UTC | 78.8 | 69.8 | 170° 17 kt | 26 | 1004.7 | -RA |
| 23:55 UTC | 78.8 | 69.8 | 170° 18 kt | 23 | 1004.4 | HZ |
| 00:15 UTC | 78.8 | 69.8 | 180° 17 kt | 25 | 1004.4 | HZ |
| 00:35 UTC | 78.8 | 69.8 | 180° 14 kt | 21 | 1004.7 | HZ |
| 00:55 UTC | 77 | 69.8 | 190° 10 kt | 21 | 1004.4 | -RA |
| 01:15 UTC | 69.8 | 66.2 | 230° 17 kt | 38 | 1005.8 | +RA FG |
| 01:35 UTC | 68 | 64.4 | 190° 9 kt | 1005.4 | -RA | |
| 01:55 UTC | 68 | 64.4 | 180° 11 kt | 1005.4 | FG | |
| 02:15 UTC | 68 | 62.6 | 180° 9 kt | 1005.8 | ||
| 02:35 UTC | 66.2 | 62.6 | 180° 7 kt | 1005.4 |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Quad Cities radar (KDVN), 120 km away, was scanning. The volume nearest the touchdown began at 00:44 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 WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are
The other tornadoes of May 15, 1998
25 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| May 15 | 11:30 AM CDT | F0 | Sioux, IA | 1.0 | 50 | $30,000 | ||
| May 15 | 12:01 PM CDT | F2 | Fillmore, NE | 9.0 | 70 | $1.0 million | ||
| May 15 | 12:30 PM CDT | F0 | York, NE | 0.5 | 30 | $250,000 | ||
| May 15 | 2:30 PM CDT | F2 | Kossuth, IA | 31.3 | 180 | $1.0 million | ||
| May 15 | 3:10 PM CDT | F1 | Faribault, MN | 0.1 | 50 | |||
| May 15 | 3:58 PM CDT | F1 | Wright, IA | 11.0 | 60 | $50,000 | ||
| May 15 | 4:00 PM CDT | F1 | Crawford, IA | 2.5 | 50 | $100,000 | ||
| May 15 | 4:00 PM CDT | F0 | Crawford, IA | 0.2 | 30 | |||
| May 15 | 4:10 PM CDT | F1 | McLeod, MN | 0.1 | 50 | $100,000 | ||
| May 15 | 4:13 PM CDT | F0 | Sioux, IA | 0.1 | 50 | |||
| May 15 | 4:15 PM CDT | F0 | Wapello, IA | 0.1 | 30 | |||
| May 15 | 4:16 PM CDT | F1 | Worth, IA | 2.8 | 50 | $150,000 | ||
| May 15 | 4:20 PM CDT | F0 | Sioux, IA | 0.1 | 50 | |||
| May 15 | 4:21 PM CDT | F0 | Sac, IA | 0.1 | 30 | |||
| May 15 | 4:40 PM CDT | F1 | Stearns, MN | 9.0 | 30 | 1 | 30 | $750,000 |
| May 15 | 4:40 PM CDT | F1 | Ramsey, MN | 13.0 | 350 | |||
| May 15 | 5:00 PM CDT | F1 | Olmsted, MN | 8.0 | 80 | $50,000 | ||
| May 15 | 5:05 PM CDT | F3 | Washington, IA | 47.0 | 400 | 47 | $15 million | |
| May 15 | 5:50 PM CDT | F3 | Buffalo, WI | 8.0 | 60 | 6 | $120,000 | |
| May 15 | 6:05 PM CDT | F1 | Dunn, WI | 18.0 | 150 | 1 | $1.9 million | |
| May 15 | 6:30 PM CDT | F0 | Jones, IA | 0.2 | 30 | $1,000 | ||
| May 15 | 7:10 PM CDT | F0 | Dubuque, IA | 0.3 | 30 | |||
| May 15 | 7:40 PM CDT | F0 | La Crosse, WI | 2.0 | 50 | 1 | $40,000 | |
| May 15 | 7:55 PM CDT | F0 | Henry, IL | 1.0 | 30 | |||
| May 15 | 8:05 PM CDT | F0 | Fulton, IL | 0.8 | 150 | $4,000 |
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.