Tornadoes · United States · Iowa · 2018

EF0 tornado, Oxford Jct, Iowa, August 16, 2018

This EF0 tornado ran 0.0 miles across Jones County on August 16, 2018, touching down at 6:08 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
August 16, 2018
Touchdown
6:08 PM CDT (23:08 UTC)
Path length
0.0 miles (0.0 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
County
Jones County
Touchdown point
41.980, -90.960
Lift-off point
41.980, -90.960
Record number
1808161708-01

The damage survey

1 damage points were recorded along this path by NWS DVN, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 75 mph.

  • Shingle damage and ventilation pipe blown off roof.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

What the Weather Service recorded

Widespread showers and thunderstorms moved across eastern Iowa ahead of a cold front during the afternoon and evening of August 16th. These storms produced rainfall of 1 to 3 inches. One thunderstorm produced a brief tornado in Jones County.

Six firefighters observed a tornado touch down on the west side of Oxford Junction, Iowa. There was damage to a pipe and a shingles on a structure. The peak estimated winds were 75 MPH.

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

The warnings

1 minute of warning. NWS DVN issued a tornado warning for this county at 23:07 UTC, 1 minute before the tornado touched down, in force until 23:23 UTC.

Issued (UTC)ExpiredProductOffice
10:07 UTC14:00 UTCDense Fog AdvisoryDVN
23:07 UTC23:23 UTCTornado WarningDVN

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 Marginal Risk. The outlook in force was issued at 19:50 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

11.1 hours before the tornado, 55 km from the path. August 16, 2018.

Skew-T log-pSkew-T log-p diagram, Davenport, at 12:00Z on 2018-08-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 873 joules per kilogram, CIN -7, lifted condensation level 556 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 2018-08-16The 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 26 square meters per square second, 0 to 6 km bulk shear 23 knots.1939Sfc1 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
873 J/kg
Mixed-layer CIN
-7 J/kg
Surface CAPE
887 J/kg
Mixed-layer LCL
556 m above ground
0-6 km bulk shear
23 kt
0-1 km bulk shear
7 kt
0-1 km storm-relative helicity
26 m²/s²
0-3 km storm-relative helicity
14 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4
0-3 km lapse rate
5.0 K/km

Open this sounding in Storm Lab

Davenport, (KDVN), 00:00Z

0.9 hours after it, 55 km from the path. August 17, 2018.

Skew-T log-pSkew-T log-p diagram, Davenport, at 00:00Z on 2018-08-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1949 joules per kilogram, CIN -2, lifted condensation level 837 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 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 2018-08-17The 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 30 square meters per square second, 0 to 6 km bulk shear 21 knots.1939Sfc1 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
1949 J/kg
Mixed-layer CIN
-2 J/kg
Surface CAPE
3496 J/kg
Mixed-layer LCL
837 m above ground
0-6 km bulk shear
21 kt
0-1 km bulk shear
11 kt
0-1 km storm-relative helicity
30 m²/s²
0-3 km storm-relative helicity
57 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.6
0-3 km lapse rate
7.1 K/km

Open this sounding in Storm Lab

The surface observations

Monticello Municipal (MXO), 31 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
21:15 UTC82.473.4210° 5 kt1012.5
21:35 UTC82.473.4270° 5 kt1012.2
21:55 UTC82.473.4280° 9 kt1012.5
22:15 UTC82.473.4290° 9 kt1012.5
22:35 UTC78.871.6310° 17 kt271012.5
22:55 UTC75.269.8340° 12 kt1013.2
23:15 UTC71.669.8360° 6 kt1013.2-RA
23:35 UTC71.671.60° 0 kt1013.9
23:55 UTC71.669.850° 6 kt1013.5
00:15 UTC71.671.680° 3 kt1013.2
00:35 UTC71.669.80° 0 kt1012.9
00:55 UTC71.669.8320° 4 kt1013.2

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

The radar

The Quad Cities radar (KDVN), 52 km away, was scanning. The volume nearest the touchdown began at 23:08 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
23:08 UTCTORNADOOxford JunctionJones, IA6 FIREFIGHTERS OBSERVED TORNADO TOUCHDOWN ON THE WEST SIDE OF OXFORD JUNCTION. DAMAGE TO PIPE AND SHINGLES ON A STRUCTURE.

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

This ground now

The live radar over the trackEvery 2018 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

The other tornadoes of August 16, 2018

3 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 164:38 PM CDTEF0Fulton, IL3.1100$30,000
August 163:00 PM PDTEF0Riverside, CA0.22
August 167:30 PM CDTEF0Barton, KS0.450

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.