EF1 tornado, Delphos to Beaconsfield, Iowa, November 11, 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

November 11, 2015

Touchdown

2:09 PM CST (20:09 UTC)

Lifted

2:20 PM CST (20:20 UTC)

On the ground

11 minutes

Path length

12.2 miles (19.6 km)

Path width

280 yards (256 m)

Deaths

0

Injuries

0

Property damage

$125,000

County

Ringgold County

Touchdown point

40.656, -94.340

Lift-off point

40.821, -94.259

Record number

1511111409-01

75 damage points were recorded along this path by NWS DMX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 110 mph.

• Damage to trees on west side of track.
• Very weak building with open face.
• Inflow into tornado, which is to the north of this damage.
• Tornado crossing point, looking north

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

Widespread wind and tornado damage occurred in central Iowa as a result of a low pressure system that raced across the state. Originally, the low pressure center developed in eastern/southeastern Colorado late Tuesday/early Wednesday and proceeded to quickly move east-northeast across Kansas before taking a more northeasterly turn as it approached southwest Iowa. Throughout the event, MUCAPE values were generally in the neighborhood of 500 J/kg. Shear values were supportive with 0-1km values and 0-6km values around 35kts and 85-90kts respectively. SRH values were also very supportive with 0-1km and 0-3km values around 350 m2/s2 and 500 m2/s2 respectively. With the speed of the system and the ample support, resulting storms were fast moving, in excess of 40mph, and of the low topped supercell variety before transitioning into a linear system as the event progressed.

This fast-moving tornado cut a 12 mile path through central Ringgold County, producing high end EF-1 damage at its peak. The beginning of the track was characterized by weak and intermittent damage, with the tornado strengthening and widening once it got north of IA Highway 2. Six farmsteads were hit along its track.

This tornado crossed through 3 counties in southern Iowa. This is the second segment in Ringgold county. This long track tornado damaged a number of farmsteads along its 22 mile long path. The tornado was at its strongest in NW Ringgold County where EF-1 damage was found. The beginning and end sections of the track were narrow and intermittent. The narrow tornado also clipped the town of Clearfield to the NW early in its life. The tornado crossed into Union county.

Survey determined tornado started in rural areas of eastern Ringgold county and produced tree damage before leaving the county. Tornado moved into Decatur 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 tornado watch, issued at 17:27 UTC and running to 21:29 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 Enhanced Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 20:06 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.

The Des Moines radar (KDMX), 120 km away, was scanning. The volume nearest the touchdown began at 20:10 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 IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

22 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.