Tornadoes · United States · Illinois · 2011

EF0 tornado, DeKalb County, Illinois, May 13, 2011

This EF0 tornado ran 0.1 miles across DeKalb County on May 13, 2011, touching down at 1:30 PM CDT and reaching 50 yards wide. It killed nobody.

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 mphthis tornado

    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 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
EF0
Date
May 13, 2011
Touchdown
1:30 PM CDT (18:30 UTC)
Lifted
1:32 PM CDT (18:32 UTC)
On the ground
2 minutes
Path length
0.1 miles (0.1 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
DeKalb County
Touchdown point
41.828, -88.776
Lift-off point
41.828, -88.774
Record number
1105131230-01

The warnings

0 minutes of warning. NWS LOT issued a tornado warning for this county at 18:30 UTC, 0 minutes before the tornado touched down, in force until 19:15 UTC.

Issued (UTC)ExpiredProductOffice
17:35 UTC18:30 UTCSevere Thunderstorm WarningLOT
18:02 UTC20:54 UTCFlood AdvisoryLOT
18:17 UTC19:15 UTCSevere Thunderstorm WarningLOT
18:26 UTC18:50 UTCSevere Thunderstorm WarningLOT
18:30 UTC19:15 UTCTornado WarningLOT
18:33 UTC00:30 UTCFlash Flood WarningLOT
18:45 UTC19:20 UTCSevere Thunderstorm WarningLOT

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 General Thunderstorms Risk. The outlook in force was issued at 16:22 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.

Davenport, (KDVN), 12:00Z

6.5 hours before the tornado, 145 km from the path. May 13, 2011.

Skew-T log-pSkew-T log-p diagram, Davenport, at 12:00Z on 2011-05-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 32 joules per kilogram, CIN -240, lifted condensation level 1097 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, Davenport, at 12:00Z on 2011-05-13The 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 -66 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
32 J/kg
Mixed-layer CIN
-240 J/kg
Surface CAPE
8 J/kg
Mixed-layer LCL
1097 m above ground
0-6 km bulk shear
40 kt
0-1 km bulk shear
25 kt
0-1 km storm-relative helicity
-66 m²/s²
0-3 km storm-relative helicity
16 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.4 K/km

Open this sounding in Storm Lab

Davenport, (KDVN), 00:00Z

5.5 hours after it, 145 km from the path. May 14, 2011.

Skew-T log-pSkew-T log-p diagram, Davenport, at 00:00Z on 2011-05-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 85 joules per kilogram, CIN -101, lifted condensation level 539 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, Davenport, at 00:00Z on 2011-05-14The 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 202 square meters per square second, 0 to 6 km bulk shear 34 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
85 J/kg
Mixed-layer CIN
-101 J/kg
Surface CAPE
36 J/kg
Mixed-layer LCL
539 m above ground
0-6 km bulk shear
34 kt
0-1 km bulk shear
27 kt
0-1 km storm-relative helicity
202 m²/s²
0-3 km storm-relative helicity
201 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5
0-3 km lapse rate
6.0 K/km

Open this sounding in Storm Lab

The surface observations

De Kalb (DKB), 13 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
16:35 UTC78.862.680° 9 kt141005.8
16:55 UTC7762.670° 8 kt1005.8
17:15 UTC78.862.680° 7 kt1005.1
17:35 UTC78.862.690° 7 kt1004.4
17:55 UTC7762.6350° 15 kt191004.4VCTS
18:15 UTC71.657.2360° 16 kt231004.1
18:35 UTC69.857.210° 19 kt301004.1VCTS
18:55 UTC6860.820° 9 kt1005.8VCTS
19:15 UTC6862.640° 15 kt191006.1-VCTSRA
19:35 UTC64.460.880° 11 kt1006.4-TSRA
19:55 UTC60.859160° 8 kt141007.5+TSRA
20:15 UTC60.85970° 6 kt1007.1+VCTSRA

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

The radar

The Chicago radar (KLOT), 63 km away, was scanning. The volume nearest the touchdown began at 18:27 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
17:45 UTCHAIL 0.25KingstonDekalb, IL
18:30 UTCTORNADO4 Ne ShabbonaDe Kalb, ILLOCAL MEDIA RELAYED HOME VIDEO OF A TORNADO THAT TOUCHED DOWN JUST NORTHEAST OF SHABBONA AROUND 130PM.
18:33 UTCFLOOD1 N KingstonDekalb, IL6 TO 12 INCHES OF WATER ON CHERRY VALLEY ROAD.
18:52 UTCFUNNEL CLOUDN WatermanDe Kalb, ILNORTH OF WATERMAN AT INTERSECTION OF ROUTES 23 AND 30.
19:33 UTCHAIL 0.885 Wnw MarseillesLa Salle, ILCOCORAHS OBSERVER
19:45 UTCHAIL 0.253 Sw MendotaLa Salle, IL
20:04 UTCFLASH FLOOD5 N ShabbonaDekalb, ILINTERSECTION OF SHABBONA AND KEHM ROADS CLOSED DUE TO FLOODING.
20:55 UTCFLASH FLOOD1 E ShabbonaDekalb, ILUS 30 EAST OF SHABBONA AT UNIVERSITY ROAD CLOSED DUE TO FLOODING.
21:00 UTCHEAVY RAIN 3.695 Nne ShabbonaDekalb, ILNORTHERN IL AGRONOMY RESEARCH CENTER CLIMATE REFERENCE NETWORK. SINCE 130 PM.

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 13, 2011

2 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 1312:46 PM CDTEF0Jefferson Parish, LA0.550$10,000
May 132:50 PM CDTEF0Plaquemines Parish, LA0.125$1,000

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.