EF1 tornado, Symerton to Wilton Center, Illinois, June 15, 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

June 15, 2015

Touchdown

7:32 PM CDT (00:32 UTC)

Lifted

7:39 PM CDT (00:39 UTC)

On the ground

7 minutes

Path length

4.1 miles (6.6 km)

Path width

150 yards (137 m)

Deaths

0

Injuries

0

Property damage

$100,000

County

Will County

Touchdown point

41.322, -88.027

Lift-off point

41.306, -87.951

Record number

1506151832-01

19 damage points were recorded along this path by NWS LOT, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 107 mph.

• also hardwoods snapped at top
• leaning at 45 deg angle toward SSE. also snapped hardwood limbs across road.
• continuation of tornado path
• also hardwood snapped high up in tree

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

Multiple rounds of heavy rain producing storms moved across the region during the day and evening of June 15th, with an especially intense area of extreme rainfall rates during the mid-afternoon through early evening centered on the I-88 and I-290 corridors from the IL/IA state line through Chicago. This rain resulted in widespread flash flooding, including the closure of a portion of I-290 (Eisenhower Expressway). Across the metro area, there were reports and photos of cars stranded, though no injuries were reported to the NWS. The heavy rainfall and widespread storm coverage resulted in the cancellation or delays of hundreds of commercial flights in and out of Chicago. A downburst occurred in Mendota, Illinois with winds estimated to be around 80 mph resulting in mainly tree damage. While the environment was not conducive for long-lived or powerful tornadoes, a tornado threat existed with a few supercells. This included two storms in central Cook County, primarily west of downtown Chicago. Each of these had funnel cloud reports. There was also a tornado reported near the Will/Kanakakee County border, not far from I-57. An EF-1 tornado was confirmed near Symerton Illinois. The highest rainfall amounts reported were two and a half to five inches in parts of Cook, DuPage, Kane, and Will Counties, which include a large majority of Chicago and the metropolitan area.

The tornado touched down approximately 1.4 miles east of Symerton snapping large tree limbs west of Warner Bridge Road. The tornado moved east and downed trees and a power pole along Peotone-Wilmington Road just west of Gougar Road. The tornado turned southeast and impacted a Kennel and an adjacent residence where EF-1 damage was noted due to roof and tree damage. This included multiple snapped or uprooted trees. The tornado moved toward Tully Road and flipped multiple 320 lb grain bins over a garage and into a field across Tully Road. Damage was noted to metal outbuildings. The tornado continued southeast and impacted two farmsteads near Kennedy and Cedar Roads where EF-1 damage occurred to trees and a machine shed. Metal siding and additional debris from the shed was thrown a half mile downstream where the tornado dissipated in a field.

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.

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 Marginal Risk. The outlook in force was issued at 19:50 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.

Joliet (JOT), 28 km from the path, in the two hours either side.

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

The Chicago radar (KLOT), 33 km away, was scanning. The volume nearest the touchdown began at 00:30 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 IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

3 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.