Tornadoes · United States · Minnesota · 2012

EF0 tornado, Minneota, Minnesota, April 15, 2012

This EF0 tornado ran 0.5 miles across Lyon County on April 15, 2012, touching down at 4:11 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
April 15, 2012
Touchdown
4:11 PM CDT (21:11 UTC)
Lifted
4:13 PM CDT (21:13 UTC)
On the ground
2 minutes
Path length
0.5 miles (0.8 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Lyon County
Touchdown point
44.590, -95.890
Lift-off point
44.590, -95.900
Record number
1204151511-01

What the Weather Service recorded

Thunderstorms produced large hail at scattered locations in southwest Minnesota during the afternoon of April 15th. There was also a brief tornado reported in Lyon County.

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.

The county was under a tornado watch, issued at 20:39 UTC and running to 23:30 UTC.

Issued (UTC)ExpiredProductOffice
20:05 UTC20:30 UTCSevere Thunderstorm WarningFSD
20:38 UTC21:15 UTCSevere Thunderstorm WarningFSD
20:39 UTC23:30 UTCTornado WatchFSD
20:41 UTC21:00 UTCTornado WarningFSD
21:14 UTC21:30 UTCTornado WarningFSD
03:00 UTC11:00 UTCHigh Wind WarningFSD
03:00 UTC00:42 UTCWind AdvisoryFSD

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 19:57 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

9.2 hours before the tornado, 184 km from the path. April 15, 2012.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2012-04-15Temperature 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 -8358, lifted condensation level 502 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 2012-04-15The 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 125 square meters per square second, 0 to 6 km bulk shear 79 knots.1939587897117136Sfc1 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
-8358 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
502 m above ground
0-6 km bulk shear
79 kt
0-1 km bulk shear
8 kt
0-1 km storm-relative helicity
125 m²/s²
0-3 km storm-relative helicity
222 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.3 K/km

Open this sounding in Storm Lab

Minneapolis, MN (KMPX), 00:00Z

2.8 hours after it, 184 km from the path. April 16, 2012.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2012-04-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1519 joules per kilogram, CIN -22, lifted condensation level 937 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, Minneapolis, MN at 00:00Z on 2012-04-16The 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 160 square meters per square second, 0 to 6 km bulk shear 102 knots.1939587897117136Sfc1 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
1519 J/kg
Mixed-layer CIN
-22 J/kg
Surface CAPE
604 J/kg
Mixed-layer LCL
937 m above ground
0-6 km bulk shear
102 kt
0-1 km bulk shear
26 kt
0-1 km storm-relative helicity
160 m²/s²
0-3 km storm-relative helicity
408 m²/s²
Significant tornado parameter
2.7
Supercell composite
10.7
0-3 km lapse rate
6.8 K/km

Open this sounding in Storm Lab

The surface observations

Marshall/Ryan (MML), 17 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
19:15 UTC5957.260° 10 kt990.9
19:35 UTC60.85950° 9 kt990.5
19:55 UTC5957.230° 12 kt990.2VCTS
20:15 UTC55.453.630° 17 kt20989.2
20:35 UTC55.451.830° 16 kt989.2VCTS
20:55 UTC53.651.860° 15 kt988.8TS
21:15 UTC55.451.8350° 17 kt34989.5VCTS
21:35 UTC55.451.810° 17 kt989.5
21:55 UTC55.451.8330° 15 kt18989.5
22:15 UTC53.648.2300° 18 kt21991.5
22:35 UTC51.846.4310° 19 kt991.9
22:55 UTC5046.4330° 21 kt26991.5

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

The radar

The Sioux Falls radar (KFSD), 130 km away, was scanning. The volume nearest the touchdown began at 21:08 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
20:28 UTCHAIL 15 Ne TylerLincoln, MNGROUND WAS WHITE WITH HAIL UP TO THE SIZE OF QUARTERS.
21:10 UTCHAIL 12 N GhentLyon, MN
21:11 UTCTORNADO5 N GhentLyon, MNTORNADO ON GROUND. SPOTTER 3 MILES NORTH OF GHENT LOOKING NORTH.
21:25 UTCHAIL 0.755 Ne MinneotaLyon, MN
21:28 UTCFUNNEL CLOUD3 W Redwood FallsRedwood, MN
21:50 UTCHEAVY RAIN 210 N MontevideoChippewa, MNESTIMATED 2 INCHES OF RAIN IN 30 MINUTES
22:36 UTCHAIL 0.75Sacred HeartRenville, MN

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 April 15, 2012

11 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 155:49 AM CDTEF1Osage, OK4.2200$50,000
April 159:22 AM CDTEF1Cherokee, OK14.5500$75,000
April 1511:48 AM CDTEF0Sherman, NE0.540$60,000
April 1512:37 PM CDTEF0Valley, NE0.025
April 151:05 PM CDTEF0Wheeler, NE0.135$54,000
April 151:55 PM CDTEF0Wheeler, NE0.120
April 152:27 PM CDTEF0Knox, NE0.440
April 152:35 PM CDTEF0Knox, NE0.525
April 152:40 PM CDTEF0Bon Homme, SD0.525
April 155:24 PM CDTEF0McLeod, MN0.115
April 156:11 PM CDTEF1Van Buren, AR2.3300$30,000

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.