F1 tornado, Rubicon to Hartford, Wisconsin, June 18, 2006

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 18, 2006

Touchdown

2:26 PM CDT (19:26 UTC)

Path length

5.8 miles (9.3 km)

Path width

400 yards (366 m)

Deaths

0

Injuries

1

Property damage

$4.0 million

Counties

Washington and Dodge counties

Touchdown point

43.320, -88.450

Lift-off point

43.280, -88.350

Record number

648

On a day one would not expect any tornadoes, a couple tornadoes did manage to spin up in southern Wisconsin. A fairly abnormal weather situation developed during the early afternoon hours of June 18th. After a large area of stratiform rain moved east out of Wisconsin, a line of scattered thunderstorms developed on the western edge of the rain shield. Two storms developed supercellular characteristics and produced a couple tornadoes - one that moved from Dodge County into Washington County, and another brief one in Dane county. In addition, a couple funnel clouds were reported. Specific details of both tornadoes are found above. Synoptically, a trough pushed through south-central and southeast Wisconsin during the late morning and afternoon hours. A moist airmass left behind from morning rain allowed for low cloud base heights. Sufficient low-level vertical wind shear was present for rotating storms. Once rotation was evident in the thunderstorms, tornadoes were easily formed because of low cloud heights and decent low-level CAPE.

A tornado spun up at 1326CST at a location 1.5 SSE of Rubicon about 0.2 mile south of the intersection of STH 60 and Resthaven Rd. It tracked east-southeast and exited Dodge County at 1327CST about 2.4 southeast of Rubicon (or about 0.6 mile south of where STH 60 goes east into Washington Co.). Only some minor tree damage was noted with this segment of the tornado track, which was rated F0 with winds of 35-63 knots (40-72 mph).

This tornado segment is a continuation of the Dodge County segment southeast of Rubicon. This second segment entered Washington County at a location 2.0 miles west of Hartford (about 0.6 mile south of where STH 60 goes east into Dodge Co.) and headed east-southeast through the southern part of the city of Hartford. The tornado strengthened to a high end F1 as it passed through the city. Around 147 residences sustained at least some damage ranging from tree damage to severe structural damage. Ten businesses also sustained structural damage. Lincoln Elementary School's roof was completely destroyed. Estimated damage amounts totaled about 4 million dollars. One person was directly injured by the tornado and two others were indirectly injured. Nobody was killed. The tornado continued east-southeast to a dissipation location 2.7 miles southeast of Hartford (about 0.1 mile southeast of the northern intersection of CTH E and K) at 1339CST. This segment of the tornado track was rated as F1 with winds of 64-97 knots (73-112 mph).

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 General Thunderstorms Risk. The outlook in force was issued at 16:16 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 Milwaukee radar (KMKX), 39 km away, was scanning. The volume nearest the touchdown began at 19:26 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.

Local storm reports within 60 km of the path, in the three hours either side.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

The live radar over the trackEvery 2006 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are

2 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.