Tornadoes · United States · Wisconsin · 2022

EF0 tornado, Stockholm, Wisconsin, May 9, 2022

This EF0 tornado ran 1.2 miles across Pepin County on May 9, 2022, touching down at 7:10 PM CDT and reaching 25 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
May 9, 2022
Touchdown
7:10 PM CDT (00:10 UTC)
Lifted
7:12 PM CDT (00:12 UTC)
On the ground
2 minutes
Path length
1.2 miles (2.0 km)
Path width
25 yards (23 m)
Deaths
0
Injuries
0
County
Pepin County
Touchdown point
44.470, -92.252
Lift-off point
44.483, -92.234
Record number
2205091810-01

The damage survey

3 damage points were recorded along this path by NWS MPX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 70 mph.

  • Estimated starting point on the Mississippi River based on video evidence.

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 dry-line/cold front that spawn a couple of tornadoes in eastern Minnesota, moved across west central Wisconsin during the evening and produced an additional three tornadoes, plus wind damage, and large hail. The tornadoes occurred near Lake Pepin, near Knapp, and between Colfax and Elk Mound in Dunn County.

The starting point was estimated based on video evidence as it began over the Mississippi River (Lake Pepin). Once onshore, the tornado knocked down or broke about one dozen trees as it moved up the river bluffs and dissipated. Maximum winds were estimated at 70 mph.

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

The warnings

2 minutes of warning. NWS MPX issued a tornado warning for this county at 00:08 UTC, 2 minutes before the tornado touched down, in force until 00:45 UTC.

The county was under a tornado watch, issued at 19:50 UTC and running to 01:52 UTC.

Issued (UTC)ExpiredProductOffice
19:50 UTC01:52 UTCTornado WatchMPX
23:48 UTC00:30 UTCSevere Thunderstorm WarningMPX
00:08 UTC00:45 UTCTornado WarningMPX
00:22 UTC00:45 UTCSevere Thunderstorm WarningMPX
00:45 UTC01:30 UTCSevere Thunderstorm WarningMPX

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 Enhanced Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 19:58 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.

Minneapolis, MN (KMPX), 00:00Z

0.2 hours before the tornado, 115 km from the path. May 10, 2022.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2022-05-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 923 joules per kilogram, CIN -42, lifted condensation level 1801 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, Minneapolis, MN at 00:00Z on 2022-05-10The 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 -82 square meters per square second, 0 to 6 km bulk shear 67 knots.1939587897Sfc1 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
923 J/kg
Mixed-layer CIN
-42 J/kg
Surface CAPE
2090 J/kg
Mixed-layer LCL
1801 m above ground
0-6 km bulk shear
67 kt
0-1 km bulk shear
27 kt
0-1 km storm-relative helicity
-82 m²/s²
0-3 km storm-relative helicity
66 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.5
0-3 km lapse rate
8.3 K/km

Open this sounding in Storm Lab

Minneapolis, MN (KMPX), 12:00Z

11.8 hours after it, 115 km from the path. May 10, 2022.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2022-05-10Temperature 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 -98406, lifted condensation level 2428 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, Minneapolis, MN at 12:00Z on 2022-05-10The 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 -45 square meters per square second, 0 to 6 km bulk shear 63 knots.1939587897Sfc1 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
-98406 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
2428 m above ground
0-6 km bulk shear
63 kt
0-1 km bulk shear
6 kt
0-1 km storm-relative helicity
-45 m²/s²
0-3 km storm-relative helicity
364 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

Red Wing (RGK), 23 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
22:15 UTC84.262.6160° 16 kt22996.6
22:35 UTC82.462.6160° 14 kt23996.3
22:55 UTC84.262.6170° 14 kt20996.6VCTS
23:15 UTC82.464.4170° 19 kt26996.6VCTSRA
23:35 UTC80.666.2170° 13 kt20995.6-VCTSRA
23:55 UTC80.662.6200° 19 kt30997-VCTSRA
00:15 UTC75.266.2210° 11 kt20998.6TSRA
00:35 UTC7768320° 4 kt999.3VCTS
00:55 UTC75.268110° 4 kt999.7
01:15 UTC75.266.20° 0 kt1001.7
01:35 UTC78.853.6310° 9 kt1002.4
01:55 UTC78.851.8300° 6 kt1002.7

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

The radar

The La Crosse radar (KARX), 111 km away, was scanning. The volume nearest the touchdown began at 00:11 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
22:50 UTCHAIL 1PrescottPierce, WIFROM SOCIAL MEDIA.
00:10 UTCTORNADO1 Se StockholmPepin, WIUPDATES PREVIOUS TORNADO REPORT FROM STOCKHOLM. SPOTTER REPORTED TORNADO ON THE MISSISSIPPI RIVER SOUTH OF STOCKHOLM. THE TORNADO WAS ALSO ON VIDEO. ABOUT ONE DOZEN TREES WERE BROKEN AS IT MOVED UP THE BLUFFS EAST OF STO
00:10 UTCTORNADOStockholmPepin, WISPOTTER REPORTED TORNADO MOVED ACROSS RIVER SOUTH OF STOCKHOLM. TIME ESTIMATED VIA RADAR.
00:25 UTCTORNADO1 E KnappDunn, WIDOZENS OF TREES WERE BROKEN, INCLUDING AT A HOME EAST OF KNAPP. THE PATH LENGTH WAS 0.7 MILES. THE TORNADO WAS RATED EF0 WITH ESTIMATED MAXIMUM WINDS OF 80 MPH.
00:32 UTCTORNADO3 Ese Cedar FallsDunn, WIUPDATES PREVIOUS TORNADO REPORT FROM 4 E CEDAR FALLS. VIDEO ON TWITTER. NWS SURVEY CONFIRMED TORNADIC DAMAGE JUST NORTH OF I-94 NEAR RUSK, WI. THE DAMAGE CONTINUED TO THE NORTHEAST THROUGH WHITETAIL GOLF COURSE. AN IRRIG
01:06 UTCHAIL 0.752 Se NelsonBuffalo, WIREPORT FROM MPING: DIME (0.75 IN.).

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

This ground now

The live radar over the trackEvery 2022 tornado in WisconsinEvery tornado in Wisconsin since 1950Warnings in force in Wisconsin nowThe forecast where you are

The other tornadoes of May 9, 2022

5 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 910:28 AM CDTEF0Polk, WI0.750
May 94:05 PM EDTEF0Monroe, FL0.015
May 95:38 PM CDTEF0Dakota, MN5.725
May 97:25 PM CDTEF0Dunn, WI0.750
May 97:32 PM CDTEF1Dunn, WI9.350

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.