Unrated tornado, Terril, Iowa, June 17, 2019

1. EF065 to 85 mph

   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. Unratedthis tornado

   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.

Rating

Unrated

Date

June 17, 2019

Touchdown

10:59 AM CDT (15:59 UTC)

Lifted

11:03 AM CDT (16:03 UTC)

On the ground

4 minutes

Path length

0.8 miles (1.2 km)

Path width

10 yards (9 m)

Deaths

0

Injuries

0

County

Dickinson County

Touchdown point

43.325, -95.029

Lift-off point

43.325, -95.014

Record number

1906170959-01

1 damage points were recorded along this path by NWS FSD, in the Damage Assessment Toolkit the survey teams carry.

• Brief landspout over barren cropland. Time and location is estimated based on shared video evidence. Image (screen shot from video) courtesy of Greg DeVore.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

An isolated thunderstorm developed late morning in a zone of enhanced near-surface vorticity, where the 0-3km CAPE allowed for rapid acceleration to the updraft. During the initial development phase, a brief landspout and funnel cloud quickly formed.

A brief landspout spun up near the intersection of 220th Street and 280th Avenue. The tornado traveled slowly eastward over barren cropland, dissipating before reaching 290th Avenue. The average path width was 10 yards.

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

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 Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 12:49 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 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.

Spencer (SPW), 23 km from the path, in the two hours either side.

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

The Sioux Falls radar (KFSD), 141 km away, was scanning. The volume nearest the touchdown began at 15:57 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.

Local storm reports within 60 km of the path, in the three hours either side.

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

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

6 more were confirmed in the United States that day.

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.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.