Tornadoes · United States · Illinois · 2011

EF1 tornado, Sangamon to Oakley, Illinois, May 25, 2011

From Sangamon to Oakley, this EF1 tornado ran 1.5 miles across Macon County on May 25, 2011, touching down at 7:39 AM CDT and reaching 75 yards wide. It killed nobody, and did $100,000 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 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.

The record

Rating
EF1
Date
May 25, 2011
Touchdown
7:39 AM CDT (12:39 UTC)
Lifted
7:42 AM CDT (12:42 UTC)
On the ground
3 minutes
Path length
1.5 miles (2.4 km)
Path width
75 yards (69 m)
Deaths
0
Injuries
0
Property damage
$100,000
County
Macon County
Touchdown point
39.880, -88.774
Lift-off point
39.899, -88.759
Record number
1105250639-01

What the Weather Service recorded

Strong thunderstorms developed along an advancing warm front between 2 AM and 9 AM on May 25th. Some of the storms became severe, producing scattered wind damage from Morgan County northeastward to Tazewell County. Other damage was noted across Champaign, Vermilion, and Douglas counties. In addition, two brief tornadoes touched down in eastern Macon County.

A tornado touched down in eastern Macon County about 6 miles east-northeast of Decatur at 7:35 AM CDT. The tornado travelled 1 mile to the northeast, damaging grain bins and outbuildings before lifting at 7:37 AM CDT.

A tornado touched down in eastern Macon County about 1.7 miles east of Oakley at 7:39 AM CDT. The tornado travelled 1.5 miles to the northeast, damaging grain bins and outbuildings before lifting at 7:42 AM 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 tornado watch, issued at 10:51 UTC and running to 17:50 UTC.

Issued (UTC)ExpiredProductOffice
10:51 UTC17:50 UTCTornado WatchILX
18:20 UTC04:17 UTCFlash Flood WatchILX
21:37 UTC01:41 UTCTornado WatchILX
22:00 UTC23:00 UTCSevere Thunderstorm WarningILX
22:37 UTC23:15 UTCSevere Thunderstorm WarningILX
22:42 UTC23:19 UTCSevere Thunderstorm WarningILX
23:01 UTC00:57 UTCFlood 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 Moderate Risk, with a 0.15 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 05:57 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), 12:00Z

0.7 hours before the tornado, 32 km from the path. May 25, 2011.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2011-05-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1832 joules per kilogram, CIN -18, lifted condensation level 561 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 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, Lincoln, IL at 12:00Z on 2011-05-25The 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 253 square meters per square second, 0 to 6 km bulk shear 40 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
1832 J/kg
Mixed-layer CIN
-18 J/kg
Surface CAPE
736 J/kg
Mixed-layer LCL
561 m above ground
0-6 km bulk shear
40 kt
0-1 km bulk shear
51 kt
0-1 km storm-relative helicity
253 m²/s²
0-3 km storm-relative helicity
222 m²/s²
Significant tornado parameter
1.6
Supercell composite
10.1
0-3 km lapse rate
5.4 K/km

Open this sounding in Storm Lab

The surface observations

Decatur (DEC), 10 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
10:54 UTC7067150° 11 kt1004.1
11:54 UTC7167170° 11 kt1003.7
12:06 UTC71.666.2160° 15 kt201003.7-TSRA BR
12:25 UTC71.666.2180° 18 kt321003.7-TSRA
12:33 UTC71.666.2160° 15 kt211003.7TS
12:40 UTC6864.4240° 30 kt431007.5TSRA BR
12:43 UTC64.462.6260° 22 kt431006.8+TSRA BR
12:50 UTC62.660.8240° 15 kt321006.8+TSRA BR
12:51 UTC62.660.8250° 15 kt321006.4+TSRA BR
12:54 UTC6361240° 10 kt231005.8+TSRA BR
12:57 UTC62.660.8240° 7 kt201005.8TSRA BR
13:54 UTC6464160° 5 kt1004.7

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

The radar

The Lincoln radar (KILX), 57 km away, was scanning. The volume nearest the touchdown began at 12:39 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
12:35 UTCTORNADO6 Ene DecaturMacon, IL2 FARM OUTBUILDINGS AND 2 GRAIN BINS DESTROYED. FROM COUNTY EMERGENCY MANAGEMENT STORM SUMMARY FOLLOWUP.
12:39 UTCTORNADO2 E OakleyMacon, IL1 OUTBUILDING DESTROYED. FROM COUNTY EMERGENCY MANAGEMENT STORM SUMMARY FOLLOWUP.
12:40 UTCTSTM WND DMG3 E CiscoPiatt, ILSEVERAL FARM OUTBUILDINGS DESTROYED. TIME ESTIMATED.
12:40 UTCHAIL 0.5Mount ZionMacon, IL
12:45 UTCTSTM WND DMG2 Nw Cerro GordoMacon, IL2 OUTBUILDINGS AND 1 GRAIN BIN DESTROYED. FROM MACON COUNTY EMERGENCY MANAGEMENT.
13:00 UTCTSTM WND DMG1 S TuscolaDouglas, ILTREE DOWN ON RAILROAD TRACKS
13:08 UTCTSTM WND DMGSadorusChampaign, ILTREES DOWN FROM COUNTY EM
13:10 UTCTSTM WND DMG1 S PesotumChampaign, ILSEMI BLOWN OVER ON I-57. ONE INJURY.
13:10 UTCTSTM WND DMGPesotumChampaign, ILSEMI BLOWN OVER ON I-57 AT MM 220
13:11 UTCTSTM WND GST 54MahometChampaign, IL
13:15 UTCTSTM WND DMGUrbanaChampaign, ILPOWERLINES AND POWER POLES DOWN
13:17 UTCTSTM WND DMG4 Se UrbanaChampaign, ILPOWERLINES DOWN

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

This ground now

The live radar over the trackEvery 2011 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

The other tornadoes of May 25, 2011

93 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 251:30 AM CDTEF1Webster, MO9.3100$20,000
May 257:35 AM CDTEF1Macon, IL1.075$165,000
May 259:04 AM CDTEF1Kankakee, IL5.850$250,000
May 259:13 AM CDTEF0Newton, IN0.120$25,000
May 259:19 AM CDTEF2Newton, IN1.9300$50,000
May 259:24 AM CDTEF1Jasper, IN2.9100$500
May 259:26 AM CDTEF1Jasper, IN1.9100$50,000
May 2510:45 AM EDTEF0Pulaski, IN0.850
May 2510:45 AM CDTEF0Miami, KS0.140$5,000
May 2511:10 AM CDTEF0Johnson, KS0.760$10,000
May 2511:22 AM CDTEF0Johnson, KS0.140
May 2511:35 AM CDTEF0Cass, MO0.140
May 2511:38 AM CDTEF0Johnson, KS0.140
May 2512:22 PM CDTEF2Pettis, MO2.150020$4.0 million
May 2512:33 PM CDTEF0Clay, MO0.140
May 2512:45 PM CDTEF0Clay, MO0.140
May 2512:52 PM CDTEF0Pettis, MO0.140
May 251:04 PM CDTEF0Cooper, MO0.140
May 251:07 PM CDTEF0Lafayette, MO0.140
May 252:15 PM CDTEF1Montgomery, MO7.1100
May 253:26 PM EDTEF0Van Wert, OH0.140
May 252:56 PM CDTEF1Oregon, MO2.5100$20,000
May 253:49 PM CDTEF3Carter, MO47.41,2002$800,000
May 254:13 PM CDTEF1Jackson, AR5.5500$40,000
May 255:15 PM EDTEF1Decatur, IN0.8600$500,000
May 255:20 PM EDTEF1Decatur, IN0.1400$250,000
May 254:35 PM CDTEF1Madison, MO5.540
May 254:37 PM CDTEF1Wayne, MO17.8150$70,000
May 254:44 PM CDTEF0Carter, MO0.550$2,000
May 254:45 PM CDTEF1Des Moines, IA4.8100$250,000
May 254:46 PM CDTEF1Madison, MO5.3440
May 254:47 PM CDTEF1Madison, MO4.3580
May 254:51 PM CDTEF0Perry, MO0.360$3,000
May 254:58 PM CDTEF0Ripley, MO0.750
May 256:00 PM EDTEF1Huron, OH8.050$250,000
May 255:00 PM CDTEF1Des Moines, IA3.650$50,000
May 255:14 PM CDTEF0Butler, MO0.740
May 256:14 PM EDTEF0Hardin, OH0.225
May 255:26 PM CDTEF1Bollinger, MO13.0250$30,000
May 256:06 PM CDTEF0McLean, IL0.925$8,000
May 256:09 PM CDTEF1McLean, IL10.375$10,000
May 257:10 PM EDTEF0Montgomery, OH0.125$5,000
May 256:18 PM CDTEF1Cape Girardeau, MO2.1250$20,000
May 256:18 PM CDTEF0St. Francis, AR1.1100
May 256:28 PM CDTEF2Jefferson, IL13.5250$4.0 million
May 256:30 PM CDTEF0Scott, MO0.450$1,000
May 257:30 PM EDTEF0Summit, OH4.250$200,000
May 256:39 PM CDTEF1Union, IL2.0125$150,000
May 256:40 PM CDTEF1Pulaski, IL5.5250$50,000
May 256:45 PM CDTEF1Pulaski, IL10.0120$40,000
May 256:48 PM CDTEF1Crittenden, AR2.5100$500,000
May 256:55 PM CDTEF2Pulaski, IL19.9325$255,000
May 256:58 PM CDTEF0Champaign, IL0.215$5,000
May 257:58 PM EDTEF3Lawrence, IN6.8300$150,000
May 255:08 PM PDTEF1Glenn, CA21.6120$200,000
May 255:12 PM PDTEF1Glenn, CA26.4120$150,000
May 257:18 PM CDTEF1Clay, IL1.075$510,000
May 257:35 PM CDTEF0Richland, IL0.210
May 257:57 PM CDTEF2Crawford, IL5.5200$920,000
May 257:58 PM CDTEF0Union Parish, LA5.5150

All 94 of them

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.