Tornadoes · United States · Minnesota · 2019

EF0 tornado, Henning Arpt, Minnesota, August 13, 2019

This EF0 tornado ran 0.3 miles across Otter Tail County on August 13, 2019, touching down at 2:25 PM CDT and reaching 100 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
August 13, 2019
Touchdown
2:25 PM CDT (19:25 UTC)
Path length
0.3 miles (0.4 km)
Path width
100 yards (91 m)
Deaths
0
Injuries
0
Crop damage
$10,000
County
Otter Tail County
Touchdown point
46.280, -95.440
Lift-off point
46.280, -95.440
Record number
1908131325-01

What the Weather Service recorded

A surface low tracked through west central Minnesota during the afternoon of August 13th. Thunderstorms rotated around the low, and one produced a weak tornado near Henning.

A tornado touched down near the Henning airport and tracked southeast for roughly a quarter of a mile across a cut hay field. The tornado threw hay onto power lines and across a portion of county road 134. Peak 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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

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 General Thunderstorms Risk. 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

7.4 hours before the tornado, 214 km from the path. August 13, 2019.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2019-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 55 joules per kilogram, CIN -110, lifted condensation level 892 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 12:00Z on 2019-08-13The 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 -30 square meters per square second, 0 to 6 km bulk shear 42 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
55 J/kg
Mixed-layer CIN
-110 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
892 m above ground
0-6 km bulk shear
42 kt
0-1 km bulk shear
6 kt
0-1 km storm-relative helicity
-30 m²/s²
0-3 km storm-relative helicity
50 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1
0-3 km lapse rate
4.3 K/km

Open this sounding in Storm Lab

Minneapolis, MN (KMPX), 00:00Z

4.6 hours after it, 214 km from the path. August 14, 2019.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2019-08-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 155 joules per kilogram, CIN -12, lifted condensation level 856 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 2019-08-14The 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 39 square meters per square second, 0 to 6 km bulk shear 28 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
155 J/kg
Mixed-layer CIN
-12 J/kg
Surface CAPE
1622 J/kg
Mixed-layer LCL
856 m above ground
0-6 km bulk shear
28 kt
0-1 km bulk shear
13 kt
0-1 km storm-relative helicity
39 m²/s²
0-3 km storm-relative helicity
33 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4
0-3 km lapse rate
7.3 K/km

Open this sounding in Storm Lab

The surface observations

Wadena Municipal (ADC), 26 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
17:35 UTC6860.80° 0 kt1013.2
17:55 UTC6860.8140° 3 kt1013.2
17:56 UTC6860.8130° 4 kt1013.2
18:16 UTC66.260.80° 0 kt1013.2-RA
18:35 UTC64.462.60° 0 kt1013.2+RA
18:55 UTC66.264.490° 5 kt1013.2VCTS
19:15 UTC66.264.490° 5 kt1013.2
19:36 UTC64.462.680° 5 kt1013.2-RA
19:55 UTC64.462.660° 4 kt1013.5-RA
20:15 UTC64.462.670° 3 kt1013.5-RA
20:16 UTC64.464.40° 0 kt1013.5-RA
20:35 UTC64.464.470° 5 kt1013.5-RA
20:55 UTC64.462.660° 5 kt1013.5RA
21:15 UTC64.464.450° 6 kt1013.5-RA

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

The radar

The Fargo/Grand Forks radar (KMVX), 199 km away, was scanning. The volume nearest the touchdown began at 19:27 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
19:22 UTCTORNADO 03 S HenningOtter Tail, MNOTTER TAIL SHERIFF RECIEVED MULTIPLE REPORTS OF A TORNADO NEAR THE HENNING AIRPORT. THE TORNADO TRACKED TO THE SOUTHEAST FOR ROUGHLY ONE QUARTER OF A MILE ACROSS A CUT OATS FIELD. THE TORNADO THREW OAT STRAW ONTO POWER L
19:25 UTCTORNADO 03 S HenningOtter Tail, MNOTTER TAIL SHERIFF RECIEVED MULTIPLE REPORTS OF A TORNADO NEAR THE HENNING AIRPORT. THE TORNADO TRACKED TO THE SOUTHEAST FOR ROUGHLY ONE QUARTER OF A MILE ACROSS A CUT HAY FIELD. THE TORNADO THREW HAY ONTO POWER LINES AN
19:25 UTCTORNADOHenningOtter Tail, MNOTTER TAIL SHERIFF RECIEVED MULTIPLE REPORTS OF A TORNADO NEAR THE HENNING AIRPORT

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

This ground now

The live radar over the trackEvery 2019 tornado in MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are

The other tornadoes of August 13, 2019

5 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 131:55 PM MDTUnratedYuma, CO2.2100
August 132:00 PM MDTUnratedYuma, CO3.5100
August 132:52 PM MDTUnratedKit Carson, CO4.2100
August 134:24 PM CDTEF0Steele, MN5.925$1,000
August 135:03 PM CDTEF0Dakota, MN0.325

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.