Tornadoes · United States · Illinois · 2015

EF2 tornado, Delavan, Illinois, July 16, 2015

This EF2 tornado ran 2.4 miles across Tazewell County on July 16, 2015, touching down at 11:39 PM CDT and reaching 250 yards wide. It killed nobody and injured 1, and did $1.2 million of property damage.

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 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 mphthis tornado

    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
EF2
Date
July 16, 2015
Touchdown
11:39 PM CDT (04:39 UTC)
Lifted
11:46 PM CDT (04:46 UTC)
On the ground
7 minutes
Path length
2.4 miles (3.8 km)
Path width
250 yards (229 m)
Deaths
0
Injuries
1
Property damage
$1.2 million
Crop damage
$10,000
County
Tazewell County
Touchdown point
40.362, -89.550
Lift-off point
40.379, -89.510
Record number
1507162239-01

The damage survey

55 damage points were recorded along this path by NWS ILX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 120 mph.

  • second story removed from house. uninhabitable.
  • crop damage a couple hundred yards past cemetery east of Springfield Rd
  • tree ripped from ground and tossed in the field in the distance in the photo photo

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

What the Weather Service recorded

A strong cold front interacting with a highly unstable airmass triggered strong to severe thunderstorms across west-central Illinois during the evening of July 16th. Scattered wind damage and flash flooding occurred mainly west of the I-55 corridor. One of the storms produced a short-lived EF-2 tornado that impacted the town of Delavan in Tazewell County, resulting in numerous homes being damaged and two minor injuries.

A tornado touched down 0.6 miles south of Delavan at 11:39 PM CDT. The tornado then moved east-northeast across the south side of Delavan, damaging 51 homes. 15 of the homes sustained severe damage, including either the roofs being completely torn off or the majority of the roof deck being lifted off. Numerous garages, outbuildings, and trees were damaged. The tornado also crossed through the Prairie Rest Cemetery, damaging grave markers and several trees before dissipating in a cornfield 2.2 miles east-northeast of Delavan at 11:46 PM CDT.

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.

The county was under a severe thunderstorm watch, issued at 22:01 UTC and running to 05:00 UTC.

Issued (UTC)ExpiredProductOffice
14:00 UTC06:00 UTCFlash Flood WatchILX
22:01 UTC05:00 UTCSevere Thunderstorm WatchILX
02:23 UTC03:15 UTCSevere Thunderstorm WarningILX
02:34 UTC03:15 UTCSevere Thunderstorm WarningILX
04:40 UTC10:45 UTCFlash Flood WarningILX
05:13 UTC05:53 UTCSevere Thunderstorm WarningILX
17:00 UTC00:00 UTCHeat AdvisoryILX

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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 00:49 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 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.

Lincoln, IL (KILX), 00:00Z

4.7 hours before the tornado, 83 km from the path. July 17, 2015.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 00:00Z on 2015-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 836 joules per kilogram, CIN -23, lifted condensation level 899 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Lincoln, IL at 00:00Z on 2015-07-17The 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 210 square meters per square second, 0 to 6 km bulk shear 38 knots.193958Sfc1 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
836 J/kg
Mixed-layer CIN
-23 J/kg
Surface CAPE
2196 J/kg
Mixed-layer LCL
899 m above ground
0-6 km bulk shear
38 kt
0-1 km bulk shear
25 kt
0-1 km storm-relative helicity
210 m²/s²
0-3 km storm-relative helicity
283 m²/s²
Significant tornado parameter
0.8
Supercell composite
9.4
0-3 km lapse rate
5.5 K/km

Open this sounding in Storm Lab

Lincoln, IL (KILX), 12:00Z

7.3 hours after it, 83 km from the path. July 17, 2015.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2015-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2277 joules per kilogram, CIN -132, lifted condensation level 1052 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Lincoln, IL at 12:00Z on 2015-07-17The 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 65 square meters per square second, 0 to 6 km bulk shear 30 knots.193958Sfc1 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
2277 J/kg
Mixed-layer CIN
-132 J/kg
Surface CAPE
3314 J/kg
Mixed-layer LCL
1052 m above ground
0-6 km bulk shear
30 kt
0-1 km bulk shear
19 kt
0-1 km storm-relative helicity
65 m²/s²
0-3 km storm-relative helicity
89 m²/s²
Significant tornado parameter
0.2
Supercell composite
2.8
0-3 km lapse rate
4.8 K/km

Open this sounding in Storm Lab

The surface observations

Lincoln (AAA), 29 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
02:55 UTC79.773.4170° 7 kt1009.8
03:15 UTC79.1673.4160° 7 kt1010.2
03:35 UTC7973.76180° 7 kt1009.8VCTS
03:55 UTC79.1674190° 8 kt1009.1VCTS
04:15 UTC79.774.310° 7 kt1010.5TS
04:35 UTC7972.68140° 4 kt1010.5VCTS
04:55 UTC78.6273.4120° 4 kt1010.5VCTS
05:15 UTC7772.68140° 5 kt1010.2TS
05:35 UTC77.5473.58170° 5 kt1010.2VCTS
05:55 UTC7873.5810° 8 kt1011.2VCTS
06:15 UTC79.773.58160° 6 kt1010.5
06:35 UTC79.774180° 7 kt1010.5

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

The radar

The Lincoln radar (KILX), 29 km away, was scanning. The volume nearest the touchdown began at 04:41 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
01:57 UTCTSTM WND DMG1 N NorrisFulton, ILCORN BLOWN OVER
01:57 UTCTSTM WND GST 801 N NorrisFulton, IL
02:15 UTCTSTM WND GST 705 Sw PeoriaPeoria, ILFROM PEORIA CO. EOC
04:20 UTCHEAVY RAIN 1.374 Ene East PeoriaTazewell, IL
04:37 UTCFUNNEL CLOUDDelavanTazewell, ILFUNNEL CLOUD REPORTED BY TRAINED SPOTTERS AND SAN JOSE FIRE DEPT. RELAYED BY LOGAN CO. DISPATCH. CORRECTED TIME.
04:37 UTCTORNADO 2DelavanTazewell, ILPATH LENGTH 1.3 MILES...WIDTH 250 YARDS. TOUCHED DOWN 0.8 MILES SOUTH OF DELAVAN AND LIFTED 1.1 MILES EAST-SOUTHEAST OF DELAVAN. 51 HOMES DAMAGED...15 SEVERELY. MOST SEVERELY DAMAGED HOMES HAD THE ROOF TORN OFF OR A MAJO
04:37 UTCTORNADODelavanTazewell, ILNUMEROUS STRUCTURES HEAVILY DAMAGED ON THE SOUTHEAST SIDE OF TOWN.
04:40 UTCFUNNEL CLOUDDelavanTazewell, ILFUNNEL CLOUD REPORTED BY TRAINED SPOTTERS AND SAN JOSE FIRE DEPT. RELAYED BY LOGAN CO. DISPATCH.
04:40 UTCTORNADODelavanTazewell, IL
05:20 UTCHEAVY RAIN 44 Nw HopedaleTazewell, IL
05:25 UTCTSTM WND DMGArmingtonTazewell, ILSEVERAL TREES DOWN IN TOWN...SOME BLOCKING ROADWAYS. TIME ESTIMATED FROM RADAR.
05:28 UTCTSTM WND DMG4 Nw AtlantaLogan, ILDELAYED REPORT. SEVERAL LARGE TREE BRANCHES DOWN AND TIN ROOF BLOWN OFF OUTBUILDING. TIME ESTIMATED.
06:15 UTCHEAVY RAIN 4.5HopedaleTazewell, IL4.50 INCHES OF RAIN REPORTED IN HOPEDALE
06:15 UTCHEAVY RAIN 6HopedaleTazewell, IL5 TO 6 INCHES OF RAIN REPORTED IN HOPEDALE

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

This ground now

The live radar over the trackEvery 2015 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

The other tornadoes of July 16, 2015

8 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
July 165:14 PM CDTEF0Henry, IA1.510
July 166:09 PM CDTEF1Henderson, IL0.8100$25,000
July 166:49 PM CDTEF1Warren, IL1.450$2,000
July 167:00 PM CDTEF1Rock Island, IL1.1200$2,000
July 167:09 PM CDTEF2Warren, IL1.7300$150,000
July 167:13 PM CDTEF2Warren, IL6.07001$1.5 million
July 168:34 PM CDTEF0Mitchell, IA2.140$40,000
July 168:48 PM CDTEF0Whiteside, IL0.610

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.