Tornadoes · United States · Wisconsin · 2020

EF0 tornado, Rouse, Wisconsin, September 25, 2020

This EF0 tornado ran 0.8 miles across Iron County on September 25, 2020, touching down at 7:52 PM CDT and reaching 50 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
September 25, 2020
Touchdown
7:52 PM CDT (00:52 UTC)
Lifted
7:54 PM CDT (00:54 UTC)
On the ground
2 minutes
Path length
0.8 miles (1.3 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Iron County
Touchdown point
46.340, -90.450
Lift-off point
46.340, -90.440
Record number
2009251852-01

The damage survey

1 damage points were recorded along this path by NWS DLH, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 85 mph.

  • Numerous trees reported downed across a swath of land on Caroline Lake Road.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

What the Weather Service recorded

A strong, late season cold front worked through the Northland on the evening of the 25th. Ample shear was in place along with cold air aloft to lead to the development of storms that were efficient hail producers across parts of northwest Wisconsin. One of the storms was able to tap into the strong shear and produce a brief, weak tornado that produced tree damage near Upson.

A brief, weak tornado caused tree damage across mainly county-owned forested land southwest of Upson.

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.

Issued (UTC)ExpiredProductOffice
23:53 UTC00:45 UTCSevere Thunderstorm WarningDLH
00:26 UTC00:48 UTCTornado WarningDLH
00:48 UTC01:30 UTCSevere Thunderstorm WarningDLH
01:25 UTC02:15 UTCSevere Thunderstorm WarningDLH
02:14 UTC02:50 UTCSevere Thunderstorm WarningDLH

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 19:40 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), 00:00Z

0.9 hours before the tornado, 276 km from the path. September 26, 2020.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 00:00Z on 2020-09-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -81640, lifted condensation level 1640 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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 2020-09-26The 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 107 square meters per square second, 0 to 6 km bulk shear 33 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
0 J/kg
Mixed-layer CIN
-81640 J/kg
Surface CAPE
16 J/kg
Mixed-layer LCL
1640 m above ground
0-6 km bulk shear
33 kt
0-1 km bulk shear
24 kt
0-1 km storm-relative helicity
107 m²/s²
0-3 km storm-relative helicity
220 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.7 K/km

Open this sounding in Storm Lab

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

11.1 hours after it, 276 km from the path. September 26, 2020.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 12:00Z on 2020-09-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 87 joules per kilogram, CIN -480, lifted condensation level 1032 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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 2020-09-26The 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 108 square meters per square second, 0 to 6 km bulk shear 47 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
87 J/kg
Mixed-layer CIN
-480 J/kg
Surface CAPE
8 J/kg
Mixed-layer LCL
1032 m above ground
0-6 km bulk shear
47 kt
0-1 km bulk shear
17 kt
0-1 km storm-relative helicity
108 m²/s²
0-3 km storm-relative helicity
116 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.9 K/km

Open this sounding in Storm Lab

The surface observations

Ironwood (IWD), 32 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
22:55 UTC210° 8 kt1003.7
22:56 UTC7264220° 8 kt1003.7
23:00 UTC220° 5 kt1003.7
23:05 UTC200° 5 kt1003.7
23:10 UTC210° 5 kt1003.7
23:15 UTC240° 5 kt1004.1
23:20 UTC71.664.4240° 6 kt1004.1-TSRA
23:25 UTC220° 4 kt1003.7+RA
23:30 UTC200° 5 kt1003.4RA
23:35 UTC210° 5 kt1003-RA
23:40 UTC270° 7 kt1003-RA
23:41 UTC6864.4280° 9 kt1003-RA
23:45 UTC300° 9 kt1002.7-RA
23:50 UTC300° 5 kt1002.7
23:55 UTC310° 5 kt1002.7
23:56 UTC6462310° 4 kt1002.7
00:00 UTC340° 5 kt1002.7
00:05 UTC330° 5 kt1002.7
00:07 UTC60.860.8330° 5 kt1002.7
00:10 UTC320° 8 kt1003
00:15 UTC330° 2 kt1003
00:20 UTC0° 0 kt1002.4
00:30 UTC0° 0 kt1002.4
00:35 UTC360° 5 kt1002.7
00:38 UTC60.859360° 7 kt1003.4
00:40 UTC360° 8 kt1003
00:45 UTC350° 5 kt1003.7
00:50 UTC330° 7 kt1003.7-RA
00:55 UTC 331004.4RA
00:56 UTC5857320° 28 kt331004.7VCTS +RA
01:00 UTC 19 kt1006.1+RA BR
01:05 UTC 15 kt211006.1+RA BR
01:10 UTC 9 kt1006.1+RA BR
01:13 UTC57.255.430° 14 kt231005.4VCTS +RA BR
01:15 UTC 15 kt211005.1RA BR
01:20 UTC 11 kt1005.4RA
01:24 UTC57.255.450° 9 kt221005.4VCTS -RA
01:25 UTC 10 kt171005.4-RA
01:30 UTC40° 10 kt1005.4-RA
01:35 UTC10° 5 kt1006.4RA
01:40 UTC80° 8 kt1005.8RA
01:41 UTC55.455.480° 8 kt1005.8VCTS RA
01:45 UTC100° 7 kt1006.1RA
01:50 UTC80° 7 kt1006.1+RA
01:55 UTC100° 5 kt1006.4-RA
01:56 UTC5756100° 6 kt1006.4-TSRA
02:00 UTC110° 5 kt1006.4-RA
02:04 UTC57.255.4130° 8 kt1006.4VCTS -RA
02:05 UTC130° 8 kt1006.4-RA
02:10 UTC90° 5 kt1006.1+RA BR
02:14 UTC57.255.4110° 6 kt1006.1-RA BR
02:15 UTC120° 8 kt1006.1-RA BR
02:20 UTC110° 8 kt1006.1-RA
02:25 UTC110° 8 kt1006.1-RA
02:30 UTC120° 8 kt1006.1-RA
02:35 UTC110° 7 kt1006.1
02:40 UTC120° 8 kt1006.1
02:45 UTC100° 5 kt1005.8
02:50 UTC110° 7 kt1005.8

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

The radar

The Duluth radar (KDLH), 146 km away, was scanning. The volume nearest the touchdown began at 00:51 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
00:11 UTCHAIL 0.251 Nnw SanbornAshland, WI
00:50 UTCHAIL 0.7MellenAshland, WI
00:51 UTCTSTM WND DMG3 Sw UpsonIron, WIDELAYED REPORT. NUMEROUS TREES DOWN AND TANGLED. TIME ESTIMATED FROM RADAR DATA.
00:51 UTCTORNADO3 Sw UpsonIron, WIEMERGENCY MANAGEMENT CONFIRMED TORNADO-LIKE DAMAGE ACROSS A FEW ACRES. TORNADO DAMAGE RATING NOT YET KNOWN PENDING ADDITIONAL INFORMATION. TIME ESTIMATED FROM RADAR DATA.
00:52 UTCTORNADO3 Sw UpsonIron, WIA BRIEF, WEAK TORNADO CAUSED TREE DAMAGE ACROSS MAINLY COUNTY-OWNED FORESTED LAND SOUTHWEST OF UPSON.
00:55 UTCHAIL 1UpsonIron, WICORRECTS PREVIOUS HAIL REPORT FROM UPSON. HAIL OCCURRED OVER A 15 MINUTE PERIOD THROUGH 8 PM.
00:55 UTCHAIL 23 Nw MorseAshland, WI
01:00 UTCTSTM WND DMG3 S MellenAshland, WITREE DOWN ON HIGHWAY 77.
01:00 UTCHAIL 1UpsonIron, WI
01:48 UTCHAIL 0.75MercerIron, WICORRECTS PREVIOUS HAIL REPORT FROM MERCER. REPORT FROM MPING: DIME (0.75 IN.).
01:48 UTCHAIL 0.75MercerIron, WIREPORT FROM MPING: DIME (0.75 IN.).
01:51 UTCHAIL 0.72 Ene MercerIron, WI
02:00 UTCHAIL 0.5MercerIron, WICORRECTS PREVIOUS HAIL REPORT FROM MERCER. REPORT FROM MPING: HALF-INCH (0.50 IN.).
02:00 UTCHAIL 0.5MercerIron, WIREPORT FROM MPING: HALF-INCH (0.50 IN.).
02:01 UTCHAIL 0.75MercerIron, WICORRECTS PREVIOUS HAIL REPORT FROM MERCER. REPORT FROM MPING: DIME (0.75 IN.).
02:01 UTCHAIL 0.75MercerIron, WIREPORT FROM MPING: DIME (0.75 IN.).
02:02 UTCHAIL 0.75MercerIron, WICORRECTS PREVIOUS HAIL REPORT FROM MERCER. REPORT FROM MPING: DIME (0.75 IN.).
02:02 UTCHAIL 0.75MercerIron, WIREPORT FROM MPING: DIME (0.75 IN.).
02:03 UTCHAIL 0.75MercerIron, WICORRECTS PREVIOUS HAIL REPORT FROM MERCER. REPORT FROM MPING: DIME (0.75 IN.).
02:03 UTCHAIL 0.75MercerIron, WIREPORT FROM MPING: DIME (0.75 IN.).
02:03 UTCHAIL 1MercerIron, WICORRECTS PREVIOUS HAIL REPORT FROM MERCER. REPORT FROM MPING: QUARTER (1.00 IN.).
02:03 UTCHAIL 1MercerIron, WIREPORT FROM MPING: QUARTER (1.00 IN.).
02:04 UTCHAIL 1.25MercerIron, WIREPORT FROM MPING: HALF DOLLAR (1.25 IN.).
02:05 UTCHAIL 1.25MercerIron, WICORRECTS PREVIOUS HAIL REPORT FROM MERCER. REPORT FROM MPING: HALF DOLLAR (1.25 IN.).
02:05 UTCHAIL 1.25MercerIron, WIREPORT FROM MPING: HALF DOLLAR (1.25 IN.).
02:06 UTCHAIL 1.25MercerIron, WI
02:09 UTCHAIL 0.71 S MercerIron, WI
02:10 UTCHAIL 1MercerIron, WICORRECTS PREVIOUS HAIL REPORT FROM MERCER. REPORT FROM MPING: QUARTER (1.00 IN.).
02:10 UTCHAIL 1MercerIron, WIREPORT FROM MPING: QUARTER (1.00 IN.).
02:10 UTCTSTM WND DMGPresque IsleVilas, WINUMEROUS TREES DOWN AROUND THE TOWN AND COUNTY ROAD W
02:12 UTCHAIL 0.75MercerIron, WICORRECTS PREVIOUS HAIL REPORT FROM MERCER. REPORT FROM MPING: DIME (0.75 IN.).
02:12 UTCHAIL 0.75MercerIron, WIREPORT FROM MPING: DIME (0.75 IN.).
02:15 UTCHAIL 0.72 Ene MercerIron, WI

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

This ground now

The live radar over the trackEvery 2020 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are

The other tornadoes of September 25, 2020

1 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
September 253:24 PM EDTEF0Horry, SC0.225$3,000

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.