Tornadoes · United States · Missouri · 2011

EF0 tornado, Washburn, Missouri, September 18, 2011

This EF0 tornado ran 0.0 miles across Barry County on September 18, 2011, touching down at 5:30 PM CDT and reaching 10 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
September 18, 2011
Touchdown
5:30 PM CDT (22:30 UTC)
Lifted
5:31 PM CDT (22:31 UTC)
On the ground
1 minutes
Path length
0.0 miles (0.0 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
County
Barry County
Touchdown point
36.575, -94.019
Lift-off point
36.575, -94.018
Record number
1109181630-01

What the Weather Service recorded

An isolated supercell thunderstorm produced localized wind damage, large hail, and a brief tornado over Barry County. Other strong storms in the area produced heavy rainfall and a deadly lightning strike which killed some livestock.

A trained weather spotter and volunteer fire department saw a brief touchdown of a tornado across Highway 90 near the intersection of Highway NN. No damage was reported with this brief touchdown as it was over an open field. Local fire department and law enforcement witnessed this brief tornado in open areas along with funnel clouds reported with this same storm.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

11 minutes of warning. NWS SGF issued a tornado warning for this county at 22:19 UTC, 11 minutes before the tornado touched down, in force until 22:45 UTC.

The county was under a severe thunderstorm watch, issued at 20:30 UTC and running to 00:34 UTC.

Issued (UTC)ExpiredProductOffice
20:30 UTC00:34 UTCSevere Thunderstorm WatchSGF
22:02 UTC22:45 UTCSevere Thunderstorm WarningSGF
22:19 UTC22:45 UTCTornado WarningSGF
22:40 UTC23:03 UTCTornado WarningSGF

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 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:59 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.

Springfield, MO (KSGF), 12:00Z

10.5 hours before the tornado, 41 km from the path. September 18, 2011.

Skew-T log-pSkew-T log-p diagram, Springfield, MO at 12:00Z on 2011-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -73688, lifted condensation level 1001 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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, Springfield, MO at 12:00Z on 2011-09-18The 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 228 square meters per square second, 0 to 6 km bulk shear 20 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
0 J/kg
Mixed-layer CIN
-73688 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1001 m above ground
0-6 km bulk shear
20 kt
0-1 km bulk shear
35 kt
0-1 km storm-relative helicity
228 m²/s²
0-3 km storm-relative helicity
350 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.0 K/km

Open this sounding in Storm Lab

Springfield, MO (KSGF), 00:00Z

1.5 hours after it, 41 km from the path. September 19, 2011.

Skew-T log-pSkew-T log-p diagram, Springfield, MO at 00:00Z on 2011-09-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 831 joules per kilogram, CIN -12, lifted condensation level 461 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, Springfield, MO at 00:00Z on 2011-09-19The 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 164 square meters per square second, 0 to 6 km bulk shear 41 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
831 J/kg
Mixed-layer CIN
-12 J/kg
Surface CAPE
317 J/kg
Mixed-layer LCL
461 m above ground
0-6 km bulk shear
41 kt
0-1 km bulk shear
18 kt
0-1 km storm-relative helicity
164 m²/s²
0-3 km storm-relative helicity
219 m²/s²
Significant tornado parameter
0.6
Supercell composite
4.4
0-3 km lapse rate
4.7 K/km

Open this sounding in Storm Lab

The surface observations

Rogers (Awos) (ROG), 24 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
20:57 UTC7470160° 8 kt1014.6
21:57 UTC7368150° 6 kt1013.9-RA
22:19 UTC71.669.8360° 3 kt1013.9VCTS -RA BR
22:30 UTC71.669.8350° 5 kt1014.2VCTS -RA BR
22:33 UTC71.669.8330° 4 kt1014.6VCTS -RA BR
22:41 UTC71.669.8330° 3 kt1014.6VCTS RA BR
22:57 UTC71690° 0 kt1014.6VCTS -RA BR
23:01 UTC71.669.80° 0 kt1014.6VCTS +RA BR
23:12 UTC71.669.8360° 4 kt1014.6VCTS -RA BR
23:41 UTC69.869.830° 3 kt1014.6VCTS RA BR
23:57 UTC7069130° 5 kt1015.6TSRA BR
00:13 UTC69.8680° 0 kt1015.2VCTS -RA BR
00:20 UTC69.8680° 0 kt1014.6-RA BR
00:28 UTC69.8680° 0 kt1014.9BR

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

The radar

The Springfield radar (KSGF), 92 km away, was scanning. The volume nearest the touchdown began at 22:31 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
22:30 UTCHAIL 1WashburnBarry, MOLOCAL CHURCH REPORTED QUARTER SIZE HAIL
22:32 UTCTSTM WND DMG1 W WashburnBarry, MOTREES REPORTED DOWN ON HWY 90 WEST OF WASHBURN. LOCATION APPROXIMATE. NO TREES BLOCKING THE ROAD. NO DAMAGE IN TOWN. A NUMBER OF REPORTS FROM RURAL FIRE AND THE HIGHWAY PATROL INDICATE A POSSIBLE TORNADO IN THIS AREA.

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 MissouriEvery tornado in Missouri since 1950Warnings in force in Missouri nowThe forecast where you are

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.