EF1 tornado, Pine Grove to Stangelville, Wisconsin, August 6, 2013

1. EF065 to 85 mph

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

2. EF186 to 110 mphthis tornado

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

3. EF2111 to 135 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. EF3136 to 165 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. EF4166 to 200 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. EF5over 200 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

EF1

Date

August 6, 2013

Touchdown

12:59 AM CDT (05:59 UTC)

Lifted

1:10 AM CDT (06:10 UTC)

On the ground

11 minutes

Path length

10.6 miles (17.0 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

Property damage

$50,000

Counties

Brown and Kewaunee counties

Touchdown point

44.433, -87.876

Lift-off point

44.409, -87.664

Record number

1308062359-01

A line of severe thunderstorms, known as a quasi-linear convective system (QLCS), produced six tornadoes and widespread damaging winds across east-central Wisconsin during the late night hours of August 6-7. The storms formed ahead of a cold front that also produced severe weather in Minnesota and western Wisconsin.||The tornadoes occurred within about 50 minutes--between 12:22 am and 1:10 am CDT. Hundreds of homes, businesses and farm buildings were damaged. Two injuries occurred at a campground in Waupaca County. Thousands of trees and power lines were also downed, leaving tens of thousands of people without power. The strongest tornado of the event reached EF2 intensity (winds estimated at 115 to 120 mph). This tornado caused significant damage to a church in New London. ||The six tornadoes that occurred on August 7 were the most nighttime tornadoes in a single event in northeast Wisconsin since accurate tornado records began (1950).

A tornado formed in eastern Brown County at 12:59 am CDT and moved east-southeast into Kewaunee County. A couple dozen trees were damaged and uprooted (DI 28, DOD 2 and 3) before it moved into Kewaunee County at about 1:06 am CDT, 2.9 miles southwest of Pilsen. Average path width in Brown County was 75 yards.

The tornado that formed in Brown County at 12:59 am CDT continued east-southeast into Kewaunee County, crossing the county line 2.9 miles southwest of Pilsen at 1:06 am CDT. The tornado caused the walls and roof of a barn to collapse (DI 1, DOD 6) and damaged the tops of two silos. In addition, the tornado damaged and uprooted several dozen trees along its path. Average path width in Kewaunee County was 75 yards.

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.

The county was under a severe thunderstorm watch, issued at 03:46 UTC and running to 07:24 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 General Thunderstorms Risk. The outlook in force was issued at 00:59 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 Green Bay radar (KGRB), 28 km away, was scanning. The volume nearest the touchdown began at 05:59 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 2013 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are

10 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.