Tornadoes · United States · Illinois · 1976

F4 tornado, DuPage and Cook counties, Illinois, June 13, 1976

This F4 tornado ran 3.3 miles across DuPage and Cook counties on June 13, 1976, touching down at 5:18 PM CDT and reaching 1,760 yards wide. It killed 2 people and injured 23, and did $500,000 to $5 million of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. F040 to 72 mph

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. F173 to 112 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. F2113 to 157 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. F3158 to 206 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. F4207 to 260 mphthis tornado

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. F5261 to 318 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
F4
Date
June 13, 1976
Touchdown
5:18 PM CDT (22:18 UTC)
Path length
3.3 miles (5.3 km)
Path width
1,760 yards (1609 m)
Deaths
2
Injuries
23
Property damage
$500,000 to $5 million
Counties
DuPage and Cook counties
Touchdown point
41.670, -88.000
Lift-off point
41.730, -87.920
Record number
592

The damage survey

181 damage points were recorded along this path by NWS LOT, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EFU. The highest wind the damage implies is 170 mph.

  • Swath of numerous trees damaged along Railroad Drive just south of Eastwood Drive.
  • Numerous power poles damaged along Railroad Drive.
  • 5 collapsed high voltage transmission towers in this area.
  • Aerial photo shows tree stripped down to just a trunk and a few large branches.

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

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.

Peoria Regional, IL (KPIA), 12:00Z

10.3 hours before the tornado, 179 km from the path. June 13, 1976.

Skew-T log-pSkew-T log-p diagram, Peoria Regional, IL at 12:00Z on 1976-06-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1495 joules per kilogram, CIN -112, lifted condensation level 993 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°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, Peoria Regional, IL at 12:00Z on 1976-06-13The 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 75 square meters per square second, 0 to 6 km bulk shear 37 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
1495 J/kg
Mixed-layer CIN
-112 J/kg
Surface CAPE
337 J/kg
Mixed-layer LCL
993 m above ground
0-6 km bulk shear
37 kt
0-1 km bulk shear
15 kt
0-1 km storm-relative helicity
75 m²/s²
0-3 km storm-relative helicity
85 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5
0-3 km lapse rate
5.1 K/km

Open this sounding in Storm Lab

Peoria Regional, IL (KPIA), 00:00Z

1.7 hours after it, 179 km from the path. June 14, 1976.

Skew-T log-pSkew-T log-p diagram, Peoria Regional, IL at 00:00Z on 1976-06-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2252 joules per kilogram, CIN -7, lifted condensation level 1828 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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, Peoria Regional, IL at 00:00Z on 1976-06-14The 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 55 square meters per square second, 0 to 6 km bulk shear 27 knots.19395878Sfc1 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
2252 J/kg
Mixed-layer CIN
-7 J/kg
Surface CAPE
3060 J/kg
Mixed-layer LCL
1828 m above ground
0-6 km bulk shear
27 kt
0-1 km bulk shear
10 kt
0-1 km storm-relative helicity
55 m²/s²
0-3 km storm-relative helicity
37 m²/s²
Significant tornado parameter
0.1
Supercell composite
2.1
0-3 km lapse rate
8.1 K/km

Open this sounding in Storm Lab

The surface observations

Chicago (MDW), 20 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
21:00 UTC8570170° 16 kt1011.5
22:00 UTC8371160° 13 kt1010.8
23:00 UTC8172160° 16 kt1010.5
00:00 UTC7162150° 20 kt371011.2

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

This ground now

The live radar over the trackEvery 1976 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

The other tornadoes of June 13, 1976

15 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
June 132:58 PM CDTF3Dallas, IA17.9100$50,000 to $500,000
June 133:10 PM CDTF5Jordan tornado, IA21.38809$5 million to $50 million
June 133:25 PM CDTF2Boone, IA4.5100
June 133:40 PM CDTF3Boone, IA0.1333$5,000 to $50,000
June 133:45 PM CDTF2Story, IA1.3200$5,000 to $50,000
June 133:45 PM CDTF2Cass, IA20.0100$5,000 to $50,000
June 132:50 PM MDTF0Campbell, WY0.110under $50
June 134:15 PM CDTF0Reeves, TX0.1101
June 135:00 PM CDTF2Black Hawk, IA14.0100$5,000 to $50,000
June 137:40 PM CDTF1Wood, WI24.61002$500 to $5,000
June 138:00 PM CDTF2Portage, WI0.350$500 to $5,000
June 139:00 PM CDTF1Langlade, WI21.350$500 to $5,000
June 139:00 PM CDTF1Outagamie, WI0.550$5,000 to $50,000
June 139:15 PM CDTF1Oconto, WI0.250$5,000 to $50,000
June 139:45 PM CDTF1Lincoln, WI10.850$500 to $5,000

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.