EF1 tornado, Tennyson, Indiana, April 7, 2015

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 mphthis tornado

   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.

Rating

EF1

Date

April 7, 2015

Touchdown

2:47 PM CDT (19:47 UTC)

Lifted

2:50 PM CDT (19:50 UTC)

On the ground

3 minutes

Path length

1.5 miles (2.4 km)

Path width

300 yards (274 m)

Deaths

0

Injuries

0

Property damage

$100,000

County

Warrick County

Touchdown point

38.044, -87.165

Lift-off point

38.059, -87.146

Record number

1504071347-01

19 damage points were recorded along this path by NWS PAH, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 95 mph.

• SeverL trees and tree limbs down in Gentryville
• At least a dozen - mostly mature pine trees, snapped.
• damage swath 200 plus yards wide
• damage to roof of house due to fallen tree.

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

A mesoscale convective system moved east-southeast from southern Illinois into southwest Indiana. The complex transitioned from a continuous line of storms to a more discrete storm mode, with two distinct supercells. The supercell over southwest Indiana produced three tornadoes along its track across Vanderburgh, Warrick, and Spencer Counties. The storms encountered a moderately unstable air mass and sufficient deep-layer wind shear for storm organization. Mixed-layer capes around 1000 to 1500 j/kg were supported by temperatures in the upper 70's and dew points in the lower 60's. This instability, coupled with effective wind shear near 40 knots, supported supercell activity with tornadoes.

Maximum winds were estimated near 95 mph. One barn was destroyed, and several other barns sustained major roof damage. A garage lost its roof. Several trees were blown down. The funnel was sighted from Tennyson by a trained spotter.

This tornado began along the eastern edge of Warrick County. Peak winds were estimated near 95 mph. Some trees were damaged. Most of the damage occurred during the Spencer County portion of the track. This tornado continued into Spencer County.

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. One was issued for the county at another hour that day.

The county was under a severe thunderstorm watch, issued at 18:57 UTC and running to 20:29 UTC.

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 Slight Risk. The outlook in force was issued at 16:23 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.

Huntingburg (HNB), 28 km from the path, in the two hours either side.

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

The Evansville,IN radar (KVWX), 55 km away, was scanning. The volume nearest the touchdown began at 19:47 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 2015 tornado in IndianaEvery tornado in Indiana since 1950Warnings in force in Indiana nowThe forecast where you are

8 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.