Tornadoes · United States · North Dakota · 2018

EF1 tornado, Milnor to Milnor Muni Arpt, North Dakota, July 8, 2018

From Milnor to Milnor Muni Arpt, this EF1 tornado ran 1.9 miles across Sargent County on July 8, 2018, touching down at 6:46 PM CDT and reaching 100 yards wide. It killed nobody, and did $50,000 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.

  1. EF065 to 85 mph

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. EF186 to 110 mphthis tornado

    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
EF1
Date
July 8, 2018
Touchdown
6:46 PM CDT (23:46 UTC)
Lifted
6:49 PM CDT (23:49 UTC)
On the ground
3 minutes
Path length
1.9 miles (3.1 km)
Path width
100 yards (91 m)
Deaths
0
Injuries
0
Property damage
$50,000
County
Sargent County
Touchdown point
46.260, -97.460
Lift-off point
46.253, -97.422
Record number
1807081746-01

What the Weather Service recorded

By the early evening of July 8th, a frontal boundary was draped from International Falls to southwest of Jamestown. South of this boundary, temperatures were in the mid to upper 80s with dew points in the middle 70s. Thunderstorms initially fired over Becker County, Minnesota, but other storms soon moved into southeast North Dakota as well. The storms over southeast North Dakota tracked into west central Minnesota by mid evening. These storms produced both damaging winds and hail.

A partially rain wrapped tornado tracked across Milnor Township. The tornado broken numerous branches and a tree in Milnor. Further east, tree damage was also noted just south of county road 13, along with the roof of a large farm shed. Several funnel clouds were reported as the circulation weakened.

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

The warnings

9 minutes of warning. NWS FGF issued a tornado warning for this county at 23:37 UTC, 9 minutes before the tornado touched down, in force until 00:15 UTC.

The county was under a severe thunderstorm watch, issued at 20:53 UTC and running to 02:26 UTC.

Issued (UTC)ExpiredProductOffice
20:53 UTC02:26 UTCSevere Thunderstorm WatchFGF
23:27 UTC00:19 UTCSevere Thunderstorm WarningFGF
23:37 UTC00:15 UTCTornado WarningFGF
23:41 UTC00:30 UTCTornado WarningFGF

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 19:57 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.

Aberdeen, SD (KABR), 12:00Z

11.8 hours before the tornado, 168 km from the path. July 8, 2018.

Skew-T log-pSkew-T log-p diagram, Aberdeen, SD at 12:00Z on 2018-07-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1150 joules per kilogram, CIN -332, lifted condensation level 1241 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, Aberdeen, SD at 12:00Z on 2018-07-08The 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 223 square meters per square second, 0 to 6 km bulk shear 24 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
1150 J/kg
Mixed-layer CIN
-332 J/kg
Surface CAPE
2010 J/kg
Mixed-layer LCL
1241 m above ground
0-6 km bulk shear
24 kt
0-1 km bulk shear
24 kt
0-1 km storm-relative helicity
223 m²/s²
0-3 km storm-relative helicity
232 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.9 K/km

Open this sounding in Storm Lab

Aberdeen, SD (KABR), 00:00Z

0.2 hours after it, 168 km from the path. July 9, 2018.

Skew-T log-pSkew-T log-p diagram, Aberdeen, SD at 00:00Z on 2018-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2501 joules per kilogram, CIN -53, lifted condensation level 1738 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, Aberdeen, SD at 00:00Z on 2018-07-09The 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 170 square meters per square second, 0 to 6 km bulk shear 52 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
2501 J/kg
Mixed-layer CIN
-53 J/kg
Surface CAPE
4723 J/kg
Mixed-layer LCL
1738 m above ground
0-6 km bulk shear
52 kt
0-1 km bulk shear
19 kt
0-1 km storm-relative helicity
170 m²/s²
0-3 km storm-relative helicity
237 m²/s²
Significant tornado parameter
0.9
Supercell composite
23.3
0-3 km lapse rate
7.1 K/km

Open this sounding in Storm Lab

The surface observations

Gwinner (GWR), 16 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
21:55 UTC91.475.20° 0 kt1013.5
22:15 UTC87.8770° 0 kt1013.5
22:35 UTC87.8770° 0 kt1013.2
22:55 UTC8678.80° 0 kt1012.5
23:15 UTC8678.80° 0 kt1011.5
23:35 UTC78.873.430° 24 kt311011.9
23:55 UTC75.269.8260° 11 kt271014.2HZ
00:15 UTC73.471.6350° 15 kt251014.6FG
00:35 UTC73.471.650° 7 kt121013.5
00:55 UTC71.671.680° 7 kt1014.2
01:15 UTC73.471.670° 6 kt1014.6
01:35 UTC73.471.610° 7 kt1014.6

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

The radar

The Aberdeen radar (KABR), 117 km away, was scanning. The volume nearest the touchdown began at 23:43 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
23:39 UTCTSTM WND GST 584 S OakesDickey, NDPEAK WIND GUST MEASURED BY THE NDAWN STATION 4 MILES SOUTH OF OAKES.
23:39 UTCTSTM WND DMG5 Nw StraubvilleSargent, ND12 INCH DIAMETER TREE IN SHELTER BELT SNAPPED APPROXIMATELY 5 FEET ABOVE THE GROUND. TIME APPROXIMATE BASED ON RADAR.
23:39 UTCTSTM WND DMG6 W StraubvilleDickey, NDTREE OF APPROXIMATELY 12 TO 18 INCHES IN DIAMETER PARTIALLY UPROOTED AND LEANING AT ABOUT A 45 DEGREE ANGLE. TIME APPROXIMATE BASED ON RADAR.
23:40 UTCTSTM WND DMG3 Sse OakesDickey, NDTOTAL OF 8 IRRIGATERS FLIPPED, 3 OR 4 GRAIN BINS DAMAGED. A 2 MILE WIDE SWATH OF CROP DAMAGE. SOME CAR PORTS DAMAGED. WIND APPEARED TO BE FROM THE NORTH. TIME ESTIMATED FROM RADAR.
23:40 UTCTSTM WND DMG3 Sse OakesDickey, NDTWO POWER POLES SNAPPED AT THIS LOCATION. CROPS ALSO SHREDDED/DESTROYED.
23:40 UTCTSTM WND DMG4 S OakesDickey, NDTREES DOWN AND IRRIGATERS BLOWN OVER. TIME ESTIMATED FROM RADAR. RELAYED THROUGH SOCIAL MEDIA.
23:40 UTCHAIL 1.253 S OakesDickey, ND1.4 INCHES OF RAIN FELL AS WELL. RELAYED THROUGH SOCIAL MEDIA.
23:40 UTCHAIL 1.755 S OakesDickey, NDGOLF BALL SIZE HAIL. PUBLIC REPORT RELAYED BY MEDIA. TIME ESTIMATED BASED ON RADAR.
23:40 UTCHAIL 2.754 S OakesDickey, NDBEAN CROP AND CORN CROP SHREDDED. ESTIMATED TIME FROM RADAR. RELAYED THROUGH SOCIAL MEDIA.
23:42 UTCHAIL 1.753 Se OakesDickey, NDRELAYED THROUGH SOCIAL MEDIA.
23:45 UTCHAIL 12 N MilnorRansom, ND
23:46 UTCTORNADO 1MilnorSargent, NDPARTIALLY RAIN WRAPPED TORNADO TRACKED ACROSS MILNOR TOWNSHIP. TORNADO BROKE NUMEROUS SMALL BRANCHES AND A TREE TRUNK IN THE TOWN OF MILNOR. FURTHER EAST, LARGE TREE LIMBS WERE BROKEN DOWN JUST SOUTH OF COUNTY ROAD 13 AN
23:50 UTCHAIL 1.75MilnorSargent, ND
23:53 UTCTSTM WND DMG2 Se MilnorSargent, NDWHEAT FIELD WITH SCATTERED DAMAGE.
23:58 UTCFUNNEL CLOUD3 E MilnorSargent, NDWITNESSED AT LEAST 3 FUNNELS.
00:10 UTCTSTM WND GST 552 Wsw BramptonSargent, NDPEAK WINDS MEASURED AT THE NAWN STATION NEAR BRAMPTON.
00:15 UTCTSTM WND DMG2 S BramptonSargent, NDA FEW TREES BROKEN DOWN IN SHELTER BELT. SOME WIND DRIVEN HAIL DAMAGE EVIDENT IN FIELDS ACROSS SOUTHEAST BRAMPTON TOWNSHIP.
00:15 UTCHAIL 12 N LeonardCass, ND

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 North DakotaEvery tornado in North Dakota since 1950Warnings in force in North Dakota nowThe forecast where you are

The other tornadoes of July 8, 2018

1 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
July 85:59 PM CDTEF0Cameron Parish, LA0.110

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.