Tornadoes · United States · Wisconsin · 2011

EF0 tornado, Arpin, Wisconsin, August 23, 2011

This EF0 tornado ran 0.0 miles across Wood County on August 23, 2011, touching down at 5:58 PM CDT and reaching 10 yards wide. It killed nobody.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mphthis tornado

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

  2. EF186 to 110 mph

    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.

The record

Rating
EF0
Date
August 23, 2011
Touchdown
5:58 PM CDT (22:58 UTC)
Path length
0.0 miles (0.0 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
County
Wood County
Touchdown point
44.553, -90.033
Lift-off point
44.553, -90.033
Record number
1108231658-01

What the Weather Service recorded

Severe thunderstorms formed as a strong upper level low pressure system moved across Wisconsin.

A brief tornado, witnessed by local law enforcement, touched down for less than 10 seconds in a corn field. A couple stalks of corn where thrown in the air, but no damage was reported. The tornado was rated EF0 with winds around 60 mph.

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

The warnings

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.

The county was under a tornado watch, issued at 22:20 UTC and running to 01:17 UTC.

Issued (UTC)ExpiredProductOffice
21:58 UTC22:30 UTCSevere Thunderstorm WarningGRB
22:20 UTC22:45 UTCTornado WarningGRB
22:20 UTC01:17 UTCTornado WatchGRB
23:00 UTC23:50 UTCSevere Thunderstorm WarningGRB

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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 20:03 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 air that afternoon

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.

Green Bay/Straub, WI (KGRB), 12:00Z

11.0 hours before the tornado, 153 km from the path. August 23, 2011.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 12:00Z on 2011-08-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 45 joules per kilogram, CIN -226, lifted condensation level 1187 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Green Bay/Straub, WI at 12:00Z on 2011-08-23The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 73 square meters per square second, 0 to 6 km bulk shear 27 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
45 J/kg
Mixed-layer CIN
-226 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1187 m above ground
0-6 km bulk shear
27 kt
0-1 km bulk shear
20 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
99 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1
0-3 km lapse rate
3.6 K/km

Open this sounding in Storm Lab

Green Bay/Straub, WI (KGRB), 00:00Z

1.0 hours after it, 153 km from the path. August 24, 2011.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 00:00Z on 2011-08-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1178 joules per kilogram, CIN -15, lifted condensation level 727 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Green Bay/Straub, WI at 00:00Z on 2011-08-24The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 150 square meters per square second, 0 to 6 km bulk shear 47 knots.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
1178 J/kg
Mixed-layer CIN
-15 J/kg
Surface CAPE
1451 J/kg
Mixed-layer LCL
727 m above ground
0-6 km bulk shear
47 kt
0-1 km bulk shear
21 kt
0-1 km storm-relative helicity
150 m²/s²
0-3 km storm-relative helicity
203 m²/s²
Significant tornado parameter
1.0
Supercell composite
4.4
0-3 km lapse rate
5.9 K/km

Open this sounding in Storm Lab

The radar

The La Crosse radar (KARX), 123 km away, was scanning. The volume nearest the touchdown began at 22:58 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.

What was reported nearby

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

Time (UTC)ReportWhereCountyRemark
22:01 UTCHAIL 1LoyalClark, WI
22:05 UTCTORNADO7 Nw ChiliClark, WITORNADO RATED AN EF2 WITH ESTIMATED WINDS IN THE 120 TO 130 MPH RANGE. AVERAGE WIDTH WAS AROUND 200 YARDS. TORNADO TOUCHED DOWN AROUND 505 PM 7 MILES NORTHWEST OF CHILI NEAR THE INTERSECTION OF BOBWHITE ROAD AND ROMADKA
22:15 UTCTORNADO5 Nw ChiliClark, WI
22:20 UTCTSTM WND DMG1 S ChiliClark, WI
22:30 UTCTORNADOChiliClark, WIHOUSE OFF FOUNDATION...POWER LINES DOWN...ROOFS OFF HOUSES...AND BARNS DESTROYED
22:38 UTCFUNNEL CLOUD4 Sw MarshfieldWood, WIFUNNEL LOCATED NEAR CNTY ROAD B AND BB
22:44 UTCHAIL 1.25NeillsvilleClark, WI
22:58 UTCTSTM WND DMG2 Ne ChiliClark, WIPOWER LINES DOWN. POSSIBLE TORNADO DAMAGE.
23:10 UTCLIGHTNINGWausauMarathon, WIBUSINESS ON FIRE AT 929 TOWNLINE ROAD
23:12 UTCTSTM WND DMG4 Ne AuburndaleWood, WITREES DOWN ALONG HIGHWAY H

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

This ground now

The live radar over the trackEvery 2011 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are

The other tornadoes of August 23, 2011

3 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 235:05 PM CDTEF2Clark, WI7.62002$1.4 million
August 236:56 PM CDTEF0Shawano, WI0.250
August 239:05 PM CDTEF0Calumet, WI0.5100$50,000

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.