Tornadoes · United States · Minnesota · 2012

EF0 tornado, Rushmore to Round Lake, Minnesota, May 4, 2012

From Rushmore to Round Lake, this EF0 tornado ran 1.0 miles across Nobles County on May 4, 2012, touching down at 2:03 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 4, 2012
Touchdown
2:03 PM CDT (19:03 UTC)
Lifted
2:05 PM CDT (19:05 UTC)
On the ground
2 minutes
Path length
1.0 miles (1.6 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Nobles County
Touchdown point
43.630, -95.720
Lift-off point
43.630, -95.700
Record number
1205041303-01

What the Weather Service recorded

Thunderstorms produced a variety of large hail, damaging winds, and brief tornadoes in southwest Minnesota on the afternoon of May 4th. There was also a report of flash flooding.

A brief tornado caused no reported damage.

A brief tornado caused no reported damage.

A brief tornado caused no reported damage.

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
18:43 UTC19:30 UTCSevere Thunderstorm WarningFSD
19:05 UTC22:12 UTCSevere Thunderstorm WatchFSD
19:06 UTC19:30 UTCTornado WarningFSD
19:18 UTC19:45 UTCTornado WarningFSD
20:48 UTC01:26 UTCFlash Flood WarningFSD

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 16:29 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

7.1 hours before the tornado, 216 km from the path. May 4, 2012.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2012-05-04Temperature 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 -92984, lifted condensation level 1101 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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, Minneapolis, MN at 12:00Z on 2012-05-04The 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 -52 square meters per square second, 0 to 6 km bulk shear 38 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
0 J/kg
Mixed-layer CIN
-92984 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1101 m above ground
0-6 km bulk shear
38 kt
0-1 km bulk shear
15 kt
0-1 km storm-relative helicity
-52 m²/s²
0-3 km storm-relative helicity
15 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.4 K/km

Open this sounding in Storm Lab

Minneapolis, MN (KMPX), 00:00Z

4.9 hours after it, 216 km from the path. May 5, 2012.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2012-05-05Temperature 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 -28329, lifted condensation level 1132 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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, Minneapolis, MN at 00:00Z on 2012-05-05The 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 70 square meters per square second, 0 to 6 km bulk shear 32 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
0 J/kg
Mixed-layer CIN
-28329 J/kg
Surface CAPE
166 J/kg
Mixed-layer LCL
1132 m above ground
0-6 km bulk shear
32 kt
0-1 km bulk shear
18 kt
0-1 km storm-relative helicity
70 m²/s²
0-3 km storm-relative helicity
274 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0
0-3 km lapse rate
6.2 K/km

Open this sounding in Storm Lab

The surface observations

Worthington (OTG), 11 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
17:15 UTC73.459140° 16 kt201010.5
17:35 UTC75.260.8130° 17 kt201010.2
17:55 UTC75.260.8120° 18 kt221009.8
18:15 UTC7760.8110° 16 kt201009.5
18:35 UTC75.260.8120° 18 kt241009.5VCTS
18:55 UTC75.260.8120° 15 kt231009.8TS
19:55 UTC0° 0 kt
20:15 UTC62.657.240° 9 kt141010.2TS
20:35 UTC60.857.2340° 16 kt1012.2VCTS
20:55 UTC60.855.4330° 24 kt361014.2VCTS

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

The radar

The Sioux Falls radar (KFSD), 82 km away, was scanning. The volume nearest the touchdown began at 19:02 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
18:48 UTCTSTM WND GST 591 Nne RushmoreNobles, MN
19:03 UTCTORNADO6 W WorthingtonNobles, MN
19:10 UTCTORNADO 01 N WorthingtonNobles, MNTORNADO TOUCHDOWN 3/4 MILES NORTH OF WORTHINGTON NEAR THE AIRPORT.
19:15 UTCHAIL 12 N WorthingtonNobles, MNTHUNDERSTORM WINDS FROM 30 TO 60 MILES AN HOUR. REPORTED NEAR WORTHINGTON MUNICIPAL AIRPORT
19:28 UTCTORNADO5 N Round LakeNobles, MNTORNADO TOUCHDOWN 5 MILES NORTH OF ROUND LAKE MN.
19:40 UTCTORNADO7 Sw LakefieldJackson, MN
19:45 UTCTSTM WND DMG5 W LakefieldJackson, MNROOF RIPPED OFF AN OPEN FACED HOG BARN.
19:49 UTCTORNADO2 S LakefieldJackson, MNTORNADO TOUCHDOWN 2 MILES SOUTH OF LAKEFIELD MN.
20:05 UTCTORNADO5 Se LakefieldJackson, MNBRIEF TOUCHDOWN
20:30 UTCFLASH FLOOD1 Ssw LakefieldJackson, MNWATER BEGAN FLOWING OVER HIGHWAY 86

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 4, 2012

11 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 42:10 PM CDTEF0Nobles, MN1.350
May 42:25 PM CDTEF0Nobles, MN0.550
May 42:40 PM CDTEF0Jackson, MN0.550
May 42:49 PM CDTEF0Jackson, MN0.550
May 43:05 PM CDTEF0Jackson, MN0.550
May 43:15 PM CDTEF0Sioux, IA0.550
May 43:22 PM CDTEF0Sioux, IA0.550
May 43:45 PM CDTEF0Martin, MN0.125
May 43:50 PM CDTEF0O'Brien, IA0.550
May 45:45 PM CDTEF0Faribault, MN3.450$250,000
May 45:52 PM CDTEF1Winnebago, IA0.890

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.