Tornadoes · United States · Illinois · 2011
EF1 tornado, Heyworth to Merna, Illinois, May 25, 2011
From Heyworth to Merna, this EF1 tornado ran 10.3 miles across McLean County on May 25, 2011, touching down at 6:09 PM CDT and reaching 75 yards wide. It killed nobody, and did $10,000 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.
EF065 to 85 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mphthis tornado
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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
- 6:09 PM CDT (23:09 UTC)
- Lifted
- 6:20 PM CDT (23:20 UTC)
- On the ground
- 11 minutes
- Path length
- 10.3 miles (16.6 km)
- Path width
- 75 yards (69 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $10,000
- County
- McLean County
- Touchdown point
- 40.360, -88.821
- Lift-off point
- 40.509, -88.807
- Record number
- 1105251709-01
What the Weather Service recorded
A deep area of low pressure lifting from the Plains into the Upper Midwest pulled a strong cold front eastward toward the Mississippi River during the afternoon of May 25th. Severe thunderstorms developed ahead of the cold front, as well as along a warm front lifting northward through the area. Many of the storms produced large hail up to the size of golf balls and damaging winds in excess of 60 mph. In addition, 6 tornadoes touched down across central Illinois, including an EF2 tornado that caused significant damage south of Robinson in Crawford County.
A tornado formed about 4 miles east of Heyworth. The tornado damaged a grain bin and then tracked into an open field before dissipating.
A tornado formed about 2 miles southeast of Downs. It crossed Interstate 74 and overturned a semi-truck. The tornado continued tracking to the north-northeast through open fields until it dissipated.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
18 minutes of warning. NWS ILX issued a tornado warning for this county at 22:51 UTC, 18 minutes before the tornado touched down, in force until 23:15 UTC.
The county was under a tornado watch, issued at 21:37 UTC and running to 01:41 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 10:51 UTC | 14:39 UTC | Tornado Watch | ILX |
| 18:20 UTC | 04:17 UTC | Flash Flood Watch | ILX |
| 21:37 UTC | 01:41 UTC | Tornado Watch | ILX |
| 22:42 UTC | 23:19 UTC | Severe Thunderstorm Warning | ILX |
| 22:45 UTC | 23:45 UTC | Severe Thunderstorm Warning | ILX |
| 22:51 UTC | 23:15 UTC | Tornado Warning | ILX |
| 23:12 UTC | 23:52 UTC | Tornado Warning | ILX |
| 23:15 UTC | 23:45 UTC | Severe Thunderstorm Warning | ILX |
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 19:39 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
11.2 hours before the tornado, 36 km from the path. May 25, 2011.
- 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
The surface observations
Bloomington/Norm (BMI), 10 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 21:56 UTC | 74.84 | 63 | 150° 8 kt | 1000.3 | ||
| 22:44 UTC | 73.4 | 64.4 | 100° 7 kt | 999.7 | VCTS | |
| 22:56 UTC | 72.86 | 65.84 | 70° 9 kt | 999 | -TSRA | |
| 23:03 UTC | 71.6 | 66.2 | 40° 8 kt | 998.6 | -TSRA | |
| 23:23 UTC | 62.6 | 59 | 220° 34 kt | 45 | 1002.7 | -TSRA FG |
| 23:30 UTC | 59 | 55.4 | 240° 7 kt | 1001.7 | -TSRA FG | |
| 23:39 UTC | 60.8 | 57.2 | 310° 10 kt | 1000 | -TSRA BR | |
| 23:56 UTC | 61 | 58 | 190° 3 kt | 1001 | -TSRA BR | |
| 00:56 UTC | 61 | 59 | 140° 7 kt | 1000 | -TSRA BR | |
| 01:00 UTC | 60.8 | 59 | 130° 6 kt | 1000 | -TSRA BR |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Lincoln radar (KILX), 54 km away, was scanning. The volume nearest the touchdown began at 23:09 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) | Report | Where | County | Remark |
|---|---|---|---|---|
| 22:24 UTC | HAIL 0.5 | Mount Pulaski | Logan, IL | |
| 22:25 UTC | TSTM WND DMG | Lincoln | Logan, IL | LARGE TREE LIMB BROKEN OFF...ONE FOOT IN DIAMETER...IN LINCOLN ON 5TH STREET. FROM TWO NWS EMPLOYEES. |
| 22:28 UTC | TSTM WND DMG | 2 E Lincoln | Logan, IL | TREE TOPPED AT WFO LINCOLN |
| 22:28 UTC | TSTM WND GST 60 | Chestnut | Logan, IL | |
| 22:52 UTC | TSTM WND GST 60 | 1 W Morton | Tazewell, IL | WIND GUST ESTIMATED NEAR LAMP ROAD |
| 22:52 UTC | TORNADO | 4 E Heyworth | Mclean, IL | TORNADO MOVING NORTHEAST |
| 23:06 UTC | TORNADO | 4 E Heyworth | Mclean, IL | TORNADO MOVING NORTHEAST |
| 23:09 UTC | TORNADO | 2 Se Downs | Mclean, IL | SEMI BLOWN OVER AT I-74 MILE MARKER 145. FROM COUNTY EMERGENCY MANAGEMENT STORM SUMMARY FOLLOWUP. |
| 23:11 UTC | TSTM WND DMG | Le Roy | Mclean, IL | TREE AND POWER POLES SNAPPED OFF |
| 23:13 UTC | TSTM WND DMG | 3 Se Downs | Mclean, IL | SEMI BLOWN OVER AT I-74 MILE MARKER 145 |
| 23:15 UTC | TORNADO | Holder | Mclean, IL | TORNADO MOVING NORTHEAST |
| 23:20 UTC | TSTM WND GST 52 | Bloomington | Mclean, IL | MEASURED AT KBMI |
| 23:22 UTC | TORNADO | 1 S Ellsworth | Mclean, IL | TORNADO MOVING NORTHEAST |
| 23:49 UTC | HAIL 1.75 | Seymour | Champaign, IL | |
| 23:50 UTC | TORNADO | 4 Nw Seymour | Piatt, IL | PUBLIC REPORT OF TORNADO ON GROUND...FROM CHAMPAIGN EMERGENCY MANAGEMENT |
| 23:53 UTC | TORNADO | 1 N Seymour | Champaign, IL | LOCAL FIRE DEPARTMENT SPOTTERS SIGHTED TORNADO ON GROUND MOVING EAST NEAR INTERSTATE 72...FROM CHAMPAIGN EMERGENCY MANAGEMENT |
| 23:58 UTC | TORNADO | 3 Se Mahomet | Champaign, IL | TREE DAMAGE FROM TORNADO BRIEF TOUCHDOWN. FROM COUNTY EMERGENCY MANAGEMENT STORM SUMMARY FOLLOWUP. |
| 23:59 UTC | TORNADO | 1 W Champaign | Champaign, IL | STATE POLICE SITED TORNADO ON WEST SIDE OF CHAMPAIGN |
| 00:05 UTC | HEAVY RAIN 0.9 | Bloomington | Mclean, IL | RAINFALL RECORDED IN ABOUT 15 MINUTES |
| 00:07 UTC | TSTM WND GST 62 | Savoy | Champaign, IL | WIND GUST REPORTED FROM CHAMPAIGN AIRPORT |
| 00:10 UTC | HAIL 0.5 | 1 Nw Champaign | Champaign, IL | |
| 00:18 UTC | HEAVY RAIN 1.56 | 2 Nnw Champaign | Champaign, IL | RAINFALL IN THE PAST 36 MINUTES |
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.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| May 25 | 1:30 AM CDT | EF1 | Webster, MO | 9.3 | 100 | $20,000 | ||
| May 25 | 7:35 AM CDT | EF1 | Macon, IL | 1.0 | 75 | $165,000 | ||
| May 25 | 7:39 AM CDT | EF1 | Macon, IL | 1.5 | 75 | $100,000 | ||
| May 25 | 9:04 AM CDT | EF1 | Kankakee, IL | 5.8 | 50 | $250,000 | ||
| May 25 | 9:13 AM CDT | EF0 | Newton, IN | 0.1 | 20 | $25,000 | ||
| May 25 | 9:19 AM CDT | EF2 | Newton, IN | 1.9 | 300 | $50,000 | ||
| May 25 | 9:24 AM CDT | EF1 | Jasper, IN | 2.9 | 100 | $500 | ||
| May 25 | 9:26 AM CDT | EF1 | Jasper, IN | 1.9 | 100 | $50,000 | ||
| May 25 | 10:45 AM EDT | EF0 | Pulaski, IN | 0.8 | 50 | |||
| May 25 | 10:45 AM CDT | EF0 | Miami, KS | 0.1 | 40 | $5,000 | ||
| May 25 | 11:10 AM CDT | EF0 | Johnson, KS | 0.7 | 60 | $10,000 | ||
| May 25 | 11:22 AM CDT | EF0 | Johnson, KS | 0.1 | 40 | |||
| May 25 | 11:35 AM CDT | EF0 | Cass, MO | 0.1 | 40 | |||
| May 25 | 11:38 AM CDT | EF0 | Johnson, KS | 0.1 | 40 | |||
| May 25 | 12:22 PM CDT | EF2 | Pettis, MO | 2.1 | 500 | 20 | $4.0 million | |
| May 25 | 12:33 PM CDT | EF0 | Clay, MO | 0.1 | 40 | |||
| May 25 | 12:45 PM CDT | EF0 | Clay, MO | 0.1 | 40 | |||
| May 25 | 12:52 PM CDT | EF0 | Pettis, MO | 0.1 | 40 | |||
| May 25 | 1:04 PM CDT | EF0 | Cooper, MO | 0.1 | 40 | |||
| May 25 | 1:07 PM CDT | EF0 | Lafayette, MO | 0.1 | 40 | |||
| May 25 | 2:15 PM CDT | EF1 | Montgomery, MO | 7.1 | 100 | |||
| May 25 | 3:26 PM EDT | EF0 | Van Wert, OH | 0.1 | 40 | |||
| May 25 | 2:56 PM CDT | EF1 | Oregon, MO | 2.5 | 100 | $20,000 | ||
| May 25 | 3:49 PM CDT | EF3 | Carter, MO | 47.4 | 1,200 | 2 | $800,000 | |
| May 25 | 4:13 PM CDT | EF1 | Jackson, AR | 5.5 | 500 | $40,000 | ||
| May 25 | 5:15 PM EDT | EF1 | Decatur, IN | 0.8 | 600 | $500,000 | ||
| May 25 | 5:20 PM EDT | EF1 | Decatur, IN | 0.1 | 400 | $250,000 | ||
| May 25 | 4:35 PM CDT | EF1 | Madison, MO | 5.5 | 40 | |||
| May 25 | 4:37 PM CDT | EF1 | Wayne, MO | 17.8 | 150 | $70,000 | ||
| May 25 | 4:44 PM CDT | EF0 | Carter, MO | 0.5 | 50 | $2,000 | ||
| May 25 | 4:45 PM CDT | EF1 | Des Moines, IA | 4.8 | 100 | $250,000 | ||
| May 25 | 4:46 PM CDT | EF1 | Madison, MO | 5.3 | 440 | |||
| May 25 | 4:47 PM CDT | EF1 | Madison, MO | 4.3 | 580 | |||
| May 25 | 4:51 PM CDT | EF0 | Perry, MO | 0.3 | 60 | $3,000 | ||
| May 25 | 4:58 PM CDT | EF0 | Ripley, MO | 0.7 | 50 | |||
| May 25 | 6:00 PM EDT | EF1 | Huron, OH | 8.0 | 50 | $250,000 | ||
| May 25 | 5:00 PM CDT | EF1 | Des Moines, IA | 3.6 | 50 | $50,000 | ||
| May 25 | 5:14 PM CDT | EF0 | Butler, MO | 0.7 | 40 | |||
| May 25 | 6:14 PM EDT | EF0 | Hardin, OH | 0.2 | 25 | |||
| May 25 | 5:26 PM CDT | EF1 | Bollinger, MO | 13.0 | 250 | $30,000 | ||
| May 25 | 6:06 PM CDT | EF0 | McLean, IL | 0.9 | 25 | $8,000 | ||
| May 25 | 7:10 PM EDT | EF0 | Montgomery, OH | 0.1 | 25 | $5,000 | ||
| May 25 | 6:18 PM CDT | EF1 | Cape Girardeau, MO | 2.1 | 250 | $20,000 | ||
| May 25 | 6:18 PM CDT | EF0 | St. Francis, AR | 1.1 | 100 | |||
| May 25 | 6:28 PM CDT | EF2 | Jefferson, IL | 13.5 | 250 | $4.0 million | ||
| May 25 | 6:30 PM CDT | EF0 | Scott, MO | 0.4 | 50 | $1,000 | ||
| May 25 | 7:30 PM EDT | EF0 | Summit, OH | 4.2 | 50 | $200,000 | ||
| May 25 | 6:39 PM CDT | EF1 | Union, IL | 2.0 | 125 | $150,000 | ||
| May 25 | 6:40 PM CDT | EF1 | Pulaski, IL | 5.5 | 250 | $50,000 | ||
| May 25 | 6:45 PM CDT | EF1 | Pulaski, IL | 10.0 | 120 | $40,000 | ||
| May 25 | 6:48 PM CDT | EF1 | Crittenden, AR | 2.5 | 100 | $500,000 | ||
| May 25 | 6:55 PM CDT | EF2 | Pulaski, IL | 19.9 | 325 | $255,000 | ||
| May 25 | 6:58 PM CDT | EF0 | Champaign, IL | 0.2 | 15 | $5,000 | ||
| May 25 | 7:58 PM EDT | EF3 | Lawrence, IN | 6.8 | 300 | $150,000 | ||
| May 25 | 5:08 PM PDT | EF1 | Glenn, CA | 21.6 | 120 | $200,000 | ||
| May 25 | 5:12 PM PDT | EF1 | Glenn, CA | 26.4 | 120 | $150,000 | ||
| May 25 | 7:18 PM CDT | EF1 | Clay, IL | 1.0 | 75 | $510,000 | ||
| May 25 | 7:35 PM CDT | EF0 | Richland, IL | 0.2 | 10 | |||
| May 25 | 7:57 PM CDT | EF2 | Crawford, IL | 5.5 | 200 | $920,000 | ||
| May 25 | 7:58 PM CDT | EF0 | Union Parish, LA | 5.5 | 150 |
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.