Tornadoes · United States · Minnesota · 2012

EF0 tornado, Sedan, Minnesota, May 1, 2012

This EF0 tornado ran 0.1 miles across Pope County on May 1, 2012, touching down at 4:48 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
May 1, 2012
Touchdown
4:48 PM CDT (21:48 UTC)
Lifted
4:49 PM CDT (21:49 UTC)
On the ground
1 minutes
Path length
0.1 miles (0.1 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Pope County
Touchdown point
45.580, -95.250
Lift-off point
45.580, -95.248
Record number
1205011548-01

What the Weather Service recorded

A frontal boundary that lied across central Minnesota, was the focus for showers and thunderstorms that developed near Alexandria, and moved to the east-southeast during the afternoon, and evening hours. Other thunderstorms developed across southern Minnesota during the afternoon, and early evening and produced mainly large hail. Tornadoes occurred during the mid afternoon hours, and mainly confined to areas south and east of Glenwood, Minnesota. These tornadoes were brief and caused only minor damage to local trees.

Spotters and multiple storm chasers reported a brief tornado touchdown north of Sedan, Minnesota. It was rated an EF0 with no damage.

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 21:46 UTC, 2 minutes before the tornado touched down, in force until 21:58 UTC.

The county was under a tornado watch, issued at 20:02 UTC and running to 02:24 UTC.

Issued (UTC)ExpiredProductOffice
20:02 UTC02:24 UTCTornado WatchMPX
21:12 UTC21:45 UTCSevere Thunderstorm WarningMPX
21:43 UTC22:30 UTCSevere Thunderstorm WarningMPX
21:46 UTC21:58 UTCTornado 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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:52 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), 12:00Z

9.8 hours before the tornado, 153 km from the path. May 1, 2012.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2012-05-01Temperature 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 -71616, lifted condensation level 1291 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 2012-05-01The 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 163 square meters per square second, 0 to 6 km bulk shear 45 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
-71616 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1291 m above ground
0-6 km bulk shear
45 kt
0-1 km bulk shear
34 kt
0-1 km storm-relative helicity
163 m²/s²
0-3 km storm-relative helicity
196 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

Minneapolis, MN (KMPX), 00:00Z

2.2 hours after it, 153 km from the path. May 2, 2012.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2012-05-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 279 joules per kilogram, CIN -111, lifted condensation level 1279 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 2012-05-02The 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 227 square meters per square second, 0 to 6 km bulk shear 44 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
279 J/kg
Mixed-layer CIN
-111 J/kg
Surface CAPE
763 J/kg
Mixed-layer LCL
1279 m above ground
0-6 km bulk shear
44 kt
0-1 km bulk shear
29 kt
0-1 km storm-relative helicity
227 m²/s²
0-3 km storm-relative helicity
393 m²/s²
Significant tornado parameter
0.2
Supercell composite
4.9
0-3 km lapse rate
6.8 K/km

Open this sounding in Storm Lab

The surface observations

Glenwood (GHW), 9 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
19:53 UTC73.457.2150° 17 kt1000.3
20:13 UTC71.655.4150° 16 kt231000
20:34 UTC73.455.4140° 15 kt1000.3
20:53 UTC71.655.4130° 10 kt16999.7VCTS
21:14 UTC6857.2160° 25 kt33999.7+TSRA
21:33 UTC60.851.8150° 11 kt999TSRA
21:53 UTC62.653.6110° 4 kt998.3-TSRA
22:14 UTC66.257.20° 0 kt997.6-VCTSRA
22:33 UTC66.257.2360° 5 kt998VCTS
22:54 UTC69.857.20° 0 kt998.3TS
23:14 UTC69.859110° 10 kt998VCTS
23:33 UTC69.857.2170° 12 kt22998.3

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

The radar

The Minneapolis radar (KMPX), 155 km away, was scanning. The volume nearest the touchdown began at 21:48 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
21:11 UTCHAIL 11 S GlenwoodPope, MN
21:40 UTCHAIL 0.8810 E GlenwoodPope, MNREPORTED NEAR GROVE LAKE.
21:45 UTCTORNADO3 W BrootenPope, MN
21:48 UTCTORNADOSedanPope, MNBRIEF TOUCHDOWN NEAR SEDAN
21:53 UTCHAIL 14 S Sauk CentreStearns, MN
22:07 UTCTORNADO3 Ne BrootenStearns, MN
22:19 UTCHAIL 0.88MelroseStearns, MN
22:30 UTCHAIL 11 W FreeportStearns, MN
22:30 UTCHAIL 1.75FreeportStearns, MN
22:46 UTCHAIL 1.75AlbanyStearns, MN
22:48 UTCHAIL 1.75AlbanyStearns, MNCOVERING GROUND WINDSHIELDS BROKEN ENTIRE CITY

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

This ground now

The live radar over the trackEvery 2012 tornado in MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are

The other tornadoes of May 1, 2012

16 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 11:30 AM CDTEF2Craig, OK1.01501$250,000
May 12:33 PM EDTEF0Clay, IN0.150$3,000
May 14:45 PM EDTEF0Trimble, KY1.915$25,000
May 13:59 PM CDTEF0Piatt, IL0.110
May 14:06 PM CDTEF1Champaign, IL8.175$25,000
May 15:28 PM EDTEF1Franklin, IN1.3100$250,000
May 14:40 PM CDTEF0Champaign, IL0.120
May 14:56 PM CDTEF0Stearns, MN0.975
May 15:05 PM CDTEF0Stearns, MN2.175$100,000
May 15:18 PM CDTEF0Vermilion, IL0.530$8,000
May 16:20 PM EDTEF0Warren, OH0.010$5,000
May 16:24 PM EDTEF0Warren, OH0.050$10,000
May 15:40 PM CDTEF0Wright, MN0.025
May 16:57 PM EDTEF0Fountain, IN0.150
May 17:36 PM EDTEF1Montgomery, IN0.5150$48,000
May 19:40 PM CDTEF0Clay, IA2.650$5,000

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.