Tornadoes · United States · Missouri · 2014

EF0 tornado, Rockport to Tarkio, Missouri, September 9, 2014

From Rockport to Tarkio, this EF0 tornado ran 4.9 miles across Atchison County on September 9, 2014, touching down at 5:50 PM CDT and reaching 25 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 9, 2014
Touchdown
5:50 PM CDT (22:50 UTC)
Lifted
5:57 PM CDT (22:57 UTC)
On the ground
7 minutes
Path length
4.9 miles (7.9 km)
Path width
25 yards (23 m)
Deaths
0
Injuries
0
County
Atchison County
Touchdown point
40.441, -95.453
Lift-off point
40.434, -95.361
Record number
1409091650-01

What the Weather Service recorded

During the afternoon and evening of September 9, 2014 a line of thunderstorms moved though eastern Nebraska into Iowa and northern Missouri. Along the southwestern edge of the line a strong supercell formed, producing widespread wind and hail across far northwestern Missouri. This supercell went on to produce 5 brief and weak tornadoes across northwestern Missouri before finally dissipating. The main line of convection then caused wind damage across northern Missouri through the remainder of the overnight hours. Another tornado then formed early in the morning on September 10 near Kirksville, Missouri. This tornado moved into the town and caused some minor damage to trees and residences. Once the wind and tornado threat decreased widespread heavy rain, producing up to 10 inches in some areas, caused flooding and flash flooding across much of northern Missouri, including closures to several main highways. No injuries were reported as a result of the severe weather and flooding, but the far northern part of the state received much damage on account of the winds and flooding.

A supercell moved southeastward through northwest Missouri and produced a weak tornado near the city of Tarkio, Missouri. While parts of the city saw strong winds there was not much reported damage.

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

The warnings

21 minutes of warning. NWS EAX issued a tornado warning for this county at 22:29 UTC, 21 minutes before the tornado touched down, in force until 23:00 UTC.

The county was under a tornado watch, issued at 20:34 UTC and running to 03:42 UTC.

Issued (UTC)ExpiredProductOffice
20:34 UTC03:42 UTCTornado WatchEAX
21:39 UTC22:30 UTCSevere Thunderstorm WarningEAX
22:24 UTC23:15 UTCSevere Thunderstorm WarningEAX
22:29 UTC23:00 UTCTornado WarningEAX
23:00 UTC23:30 UTCTornado WarningEAX
23:04 UTC05:00 UTCFlood AdvisoryEAX
23:12 UTC00:00 UTCSevere Thunderstorm WarningEAX
23:27 UTC04:44 UTCFlash Flood WarningEAX
23:41 UTC00:30 UTCSevere Thunderstorm WarningEAX
00:00 UTC11:52 UTCFlash Flood WatchEAX
02:39 UTC06:43 UTCFlood WarningEAX
04:39 UTC23:30 UTCFlood WarningEAX

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 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 19:53 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.

Omaha, NE (KOAX), 12:00Z

10.8 hours before the tornado, 127 km from the path. September 9, 2014.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 2014-09-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1246 joules per kilogram, CIN -266, lifted condensation level 1436 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Omaha, NE at 12:00Z on 2014-09-09The 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 71 square meters per square second, 0 to 6 km bulk shear 25 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
1246 J/kg
Mixed-layer CIN
-266 J/kg
Surface CAPE
748 J/kg
Mixed-layer LCL
1436 m above ground
0-6 km bulk shear
25 kt
0-1 km bulk shear
4 kt
0-1 km storm-relative helicity
71 m²/s²
0-3 km storm-relative helicity
96 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.8 K/km

Open this sounding in Storm Lab

Omaha, NE (KOAX), 00:00Z

1.2 hours after it, 127 km from the path. September 10, 2014.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 2014-09-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 81 joules per kilogram, CIN -243, lifted condensation level 845 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Omaha, NE at 00:00Z on 2014-09-10The 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 117 square meters per square second, 0 to 6 km bulk shear 49 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
81 J/kg
Mixed-layer CIN
-243 J/kg
Surface CAPE
212 J/kg
Mixed-layer LCL
845 m above ground
0-6 km bulk shear
49 kt
0-1 km bulk shear
12 kt
0-1 km storm-relative helicity
117 m²/s²
0-3 km storm-relative helicity
594 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1
0-3 km lapse rate
4.4 K/km

Open this sounding in Storm Lab

The surface observations

Shenandoah (SDA), 35 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
20:55 UTC78.873.460° 9 kt1004.4
21:05 UTC7775.240° 6 kt131004.7-RA
21:15 UTC7775.250° 9 kt1004.4-RA
21:25 UTC7775.250° 10 kt1004.7BR
21:35 UTC7775.270° 12 kt1004.1-RA
21:45 UTC75.273.430° 10 kt161004.7-RA
21:55 UTC75.273.410° 11 kt1004.7+RA
22:05 UTC73.471.610° 20 kt281005.4+RA
22:15 UTC686820° 25 kt321004.1+RA
22:25 UTC6868350° 16 kt301005.1+RA
22:35 UTC686810° 9 kt181005.1+RA
22:45 UTC6868 5 kt101005.8RA
22:55 UTC69.86850° 11 kt1004.1RA
23:05 UTC69.869.8 4 kt111005.1-RA
23:15 UTC69.869.8140° 6 kt1004.7-RA
23:25 UTC69.869.8160° 7 kt1005.1-RA
23:35 UTC69.869.8120° 5 kt101005.1
23:45 UTC69.868170° 4 kt1004.7-RA
23:55 UTC69.869.880° 6 kt1004.1-RA
00:05 UTC69.869.8110° 9 kt1004.1
00:15 UTC69.869.8 6 kt131003.4
00:25 UTC69.869.880° 9 kt1003
00:35 UTC69.869.880° 10 kt1002.7
00:45 UTC69.86870° 10 kt1002.7

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

The radar

The Omaha radar (KOAX), 127 km away, was scanning. The volume nearest the touchdown began at 22:48 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
22:17 UTCTSTM WND GST 602 N WatsonAtchison, MO
22:17 UTCHAIL 1.252 N WatsonAtchison, MO
22:40 UTCHAIL 12 Ne RockportAtchison, MO
22:43 UTCHAIL 13 Wnw RockportAtchison, MO
22:44 UTCHAIL 1.752 W TarkioAtchison, MOGOLF BALL SIZE HAIL/70MPH WINDS 2MILES WEST OF TARKIO. PENNY SIZE HAIL REPORTED NOW IN TARKIO.
22:50 UTCHAIL 1.252 N TarkioAtchison, MO
22:50 UTCTORNADON TarkioAtchison, MOPOSSIBLE TORNADO...FLYING DEBRIS AT LEAST 70 MPH WINDS
22:57 UTCTSTM WND GST 70TarkioAtchison, MO70 MPH WINDS SUSTAINED FOR 5 TO 7 MINUTES IN THE CITY OF TARKIO. CITY WITHOUT POWER. NICKEL SIZE HAIL UP TO GOLF BALL SIZE HAIL REPORTED AT 552PM. NICKEL SIZE HAIL FALLING NOW.
23:15 UTCTSTM WND GST 751 W FairfaxAtchison, MO
23:21 UTCTSTM WND DMGTarkioAtchison, MOSEVERAL LARGE TREES DOWN ACROSS TOWN. POWER OUT ACROSS TOWN.
23:50 UTCFLASH FLOODTarkioAtchison, MOMANY STREETS HAVE A FOOT OF WATER OVER THEM IN TARKIO AND ON AA HIGHWAY NORTH OF TARKIO.
00:10 UTCTORNADOMaitlandHolt, MOTORNADO REPORTED ON GROUND NEAR MAITLAND
00:20 UTCTSTM WND DMGMaitlandHolt, MOTREES AND POWER LINES DOWN
00:25 UTCFUNNEL CLOUDGrahamNodaway, MOHIGHWAY PATROL REPORTED SEEING A FUNNEL CLOUD NEAR GRAHAM, MO AT HWYS A AND H.
00:40 UTCTORNADO2 Sw MaitlandHolt, MODELAYED EYE WITNESS REPORT FROM OFF DUTY NWS EMPLOYEE OF TWO TORNADOES TOUCHING DOWN.
00:54 UTCFLASH FLOODRockportAtchison, MOUS HIGHWAY 111 MAIN STREET INTO ROCKPORT IMPASSABLE.
01:20 UTCHAIL 1.55 Sw BolckowAndrew, MOQUARTER TO PING PONG SIZED HAIL, HEAVY RAIN, WINDS EST 40 TO 45 MPH.

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

This ground now

The live radar over the trackEvery 2014 tornado in MissouriEvery tornado in Missouri since 1950Warnings in force in Missouri nowThe forecast where you are

The other tornadoes of September 9, 2014

6 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
September 94:29 PM CDTEF1Otoe, NE7.7965$50,000
September 97:10 PM CDTEF0Holt, MO3.030
September 97:35 PM CDTEF0Holt, MO0.125
September 97:40 PM CDTEF0Holt, MO0.125
September 99:10 PM CDTEF0Saint Charles, MO1.725
September 910:22 PM CDTEF0DeKalb, MO0.825

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.