F0 tornado, St Nazianz, Wisconsin, May 12, 2000

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.

Rating

F0

Date

May 12, 2000

Touchdown

11:43 AM CDT (16:43 UTC)

Path length

0.1 miles (0.2 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

County

Manitowoc County

Touchdown point

44.030, -88.020

Lift-off point

44.030, -88.020

Record number

220

During the mid and late morning of May 12, a high precipitation supercell thunderstorm developed in west-central Wisconsin and tracked east across the state for over two and a half hours. The storm produced a prolific path of large hail, a brief tornado, and a significant wet microburst across central and east central Wisconsin. The storm was one of the most damaging thunderstorms in Wisconsin history, producing well over $100 million in damage.The thunderstorm developed north of a warm front, which was located across the Wisconsin/Illinois border. The setup was favorable for what is known as "elevated" convection; that is, the source of the instability was aloft, and not surface-based. Elevated convection often produces large hail, and the May 12 storm was no exception.As the storm moved into central Wisconsin, numerous reports of large hail were received from Waushara and Winnebago counties. Baseball size hail was observed with the storm in Waushara county, two miles east of Coloma and in Dakota. Hail damaged many of the roofs of the more than 1,000 homes in Omro (Winnebago co.) alone.As the storm intensified, it produced extensive damage across Calumet and Manitowoc counties as microburst winds developed. Wind-driven hail shredded west-facing sides of homes and businesses that were caught in the path of the storm.The worst damage in Calumet county was in and around Chilton, where 2 inch hail and hurricane-force wind gusts (estimated near 80 mph) knocked holes in siding and tore the walls and roofs from some buildings. Over 1000 homes were damaged in the city of Chilton. Two hundred more sustained damage in the township of Charlestown.A brief tornado occurred as the storm entered Manitowoc county, but did no damage. At about 1150 a.m. CDT, microburst winds near 100 mph and 2 inch hail combined to produce very serious damage in St. Nazianz. Most of the homes in a mobile home park in St. Nazianz were overturned or knocked off their foundation by the straight-line wind. Thirty people were injured in Manitowoc county, most in St. Nazianz. In Manitowoc county, over 100 homes were destroyed by the combination of wind and hail. Many more were damaged.

Brief tornado touchdown.

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

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.

Manitowac Municipal (MTW), 29 km from the path, in the two hours either side.

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

The Green Bay radar (KGRB), 53 km away, was scanning. The volume nearest the touchdown began at 16:41 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.

The live radar over the trackEvery 2000 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are

11 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.