Tornadoes · United States · North Dakota · 2023

Unrated tornado, Voltaire, North Dakota, August 24, 2023

This Unrated tornado ran 0.8 miles across McHenry County on August 24, 2023, touching down at 2:38 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 mph

    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. Unratedthis tornado

    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
Unrated
Date
August 24, 2023
Touchdown
2:38 PM CDT (19:38 UTC)
Lifted
2:42 PM CDT (19:42 UTC)
On the ground
4 minutes
Path length
0.8 miles (1.3 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
McHenry County
Touchdown point
47.960, -100.820
Lift-off point
47.961, -100.803
Record number
2308241338-01

What the Weather Service recorded

A cold front dropped slowly through North Dakota as an upper level low moved across southern Saskatchewan, with severe thunderstorms developing along and ahead of the front. Along one boundary ahead of the front, in the Voltaire area of McHenry County, two short-lived landspout tornadoes formed. No damage was reported with the tornadoes and so by National Weather Service policy the tornadoes were rated EF Unknown. The tornadoes touched down 12 minutes apart from two different thunderstorms. Otherwise, damaging thunderstorm winds were the main threat with most of the storms, though one storm produced one-inch diameter hail near Bottineau in Bottineau County. The strongest wind gust was estimated to be 75 mph, and occurred near Twin Buttes in Dunn County, where a truck window was broken out and a snowmobile trailer was blown down a coulee.

This tornado, a landspout, touched down in an open field south-southeast of Voltaire and impacted no structures. There was no damage to evaluate and so by National Weather Service policy the tornado is rated EF Unknown. This was the first of two landspout tornadoes in the Voltaire area of McHenry County this day, 12 minutes apart, from two different thunderstorms.

This tornado, a landspout, touched down in an open field southwest of Voltaire and impacted no structures. There was no damage to evaluate and so by National Weather Service policy the tornado is rated EF Unknown. This was the second of two landspout tornadoes in the Voltaire area of McHenry County this day, 12 minutes apart, from two different thunderstorms.

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

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

Issued (UTC)ExpiredProductOffice
01:43 UTC02:10 UTCSevere Thunderstorm WarningBIS
07:22 UTC15:00 UTCDense Fog AdvisoryBIS
19:41 UTC20:15 UTCTornado WarningBIS
19:45 UTC01:00 UTCSevere Thunderstorm WatchBIS
19:55 UTC20:09 UTCTornado WarningBIS
21:09 UTC22:00 UTCSevere Thunderstorm WarningBIS
21:52 UTC22:22 UTCSevere Thunderstorm WarningBIS

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 16:30 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.

Bismarck Municip, ND (KBIS), 12:00Z

7.6 hours before the tornado, 133 km from the path. August 24, 2023.

Skew-T log-pSkew-T log-p diagram, Bismarck Municip, ND at 12:00Z on 2023-08-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 66 joules per kilogram, CIN -234, lifted condensation level 1667 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, Bismarck Municip, ND at 12:00Z on 2023-08-24The 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 -63 square meters per square second, 0 to 6 km bulk shear 45 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
66 J/kg
Mixed-layer CIN
-234 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1667 m above ground
0-6 km bulk shear
45 kt
0-1 km bulk shear
13 kt
0-1 km storm-relative helicity
-63 m²/s²
0-3 km storm-relative helicity
-116 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0
0-3 km lapse rate
3.4 K/km

Open this sounding in Storm Lab

Bismarck Municip, ND (KBIS), 00:00Z

4.4 hours after it, 133 km from the path. August 25, 2023.

Skew-T log-pSkew-T log-p diagram, Bismarck Municip, ND at 00:00Z on 2023-08-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 542 joules per kilogram, CIN -18, lifted condensation level 2128 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, Bismarck Municip, ND at 00:00Z on 2023-08-25The 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 77 square meters per square second, 0 to 6 km bulk shear 56 knots.1939587897Sfc1 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
542 J/kg
Mixed-layer CIN
-18 J/kg
Surface CAPE
2111 J/kg
Mixed-layer LCL
2128 m above ground
0-6 km bulk shear
56 kt
0-1 km bulk shear
12 kt
0-1 km storm-relative helicity
77 m²/s²
0-3 km storm-relative helicity
233 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.5
0-3 km lapse rate
9.0 K/km

Open this sounding in Storm Lab

The surface observations

Minot_intl (MOT), 48 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
17:40 UTC110° 2 kt1013.9
17:45 UTC140° 2 kt1013.5
17:50 UTC140° 4 kt1013.5
17:54 UTC8469130° 3 kt1013.5VCTS
17:55 UTC130° 2 kt1013.5
18:00 UTC180° 2 kt1013.9
18:05 UTC210° 5 kt1013.9
18:10 UTC220° 5 kt1013.9
18:12 UTC8467220° 5 kt1013.9
18:15 UTC220° 9 kt1013.9
18:20 UTC220° 10 kt1014.2
18:25 UTC220° 10 kt1013.9
18:27 UTC8265210° 10 kt1013.9VCTS
18:30 UTC170° 5 kt1013.9-RA
18:35 UTC230° 4 kt1013.5-RA
18:40 UTC210° 7 kt1013.5-RA
18:42 UTC8167200° 7 kt1013.5-RA
18:45 UTC200° 8 kt1013.5-RA
18:50 UTC210° 5 kt1013.5
18:54 UTC8265200° 7 kt1013.2
18:55 UTC200° 7 kt1013.2
19:00 UTC190° 5 kt1013.2
19:05 UTC180° 5 kt1012.9
19:08 UTC8462200° 6 kt1012.9VCTS
19:10 UTC180° 5 kt1012.9
19:15 UTC180° 9 kt1012.9
19:20 UTC170° 8 kt1012.9
19:21 UTC8566190° 7 kt1012.9TS
19:25 UTC190° 7 kt1012.9
19:30 UTC210° 7 kt1012.9
19:35 UTC200° 7 kt1012.9
19:40 UTC220° 9 kt1012.9
19:45 UTC200° 8 kt1013.2
19:50 UTC220° 7 kt1013.5
19:54 UTC8665240° 7 kt1013.2VCTS
19:55 UTC220° 7 kt1013.2
20:00 UTC220° 5 kt1013.2
20:05 UTC0° 0 kt1012.9
20:09 UTC8566 4 kt1012.9
20:10 UTC20° 2 kt1012.9
20:15 UTC50° 5 kt1012.9
20:20 UTC30° 4 kt1012.9
20:25 UTC40° 8 kt1012.9
20:30 UTC30° 5 kt1012.9
20:35 UTC170° 5 kt1012.5
20:40 UTC170° 5 kt1012.5
20:45 UTC180° 2 kt1012.2
20:45 UTC8463180° 3 kt1012.2VCTS
20:50 UTC210° 10 kt1012.9
20:54 UTC8559220° 8 kt1013.2VCTS
20:55 UTC230° 8 kt1013.2
21:00 UTC 311013.9
21:05 UTC 231013.5
21:09 UTC7258330° 14 kt311013.9TS
21:10 UTC320° 13 kt1013.9
21:15 UTC320° 9 kt1013.9-RA
21:18 UTC6959310° 7 kt201014.2VCTS -RA
21:20 UTC310° 8 kt1014.6-RA
21:25 UTC310° 9 kt1014.6-RA
21:30 UTC330° 10 kt1014.2-RA
21:35 UTC320° 7 kt1014.2-RA

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

The radar

The Minot AFB radar (KMBX), 48 km away, was scanning. The volume nearest the touchdown began at 19:39 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
19:38 UTCTORNADO4 Sse VoltaireMchenry, NDShort lived landspout tornado.
19:54 UTCTORNADO7 Nnw RusoMchenry, NDShort lived landspout tornado.
21:30 UTCTSTM WND GST 602 Nne GranvilleMchenry, NDWinds lasted about 15 minutes.

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

This ground now

The live radar over the trackEvery 2023 tornado in North DakotaEvery tornado in North Dakota since 1950Warnings in force in North Dakota nowThe forecast where you are

The other tornadoes of August 24, 2023

21 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 242:54 PM CDTUnratedMcHenry, ND0.650
August 244:55 PM EDTEF0Collier, FL0.850$100,000
August 248:15 PM EDTEF1Kent, MI8.7100$10 million
August 249:29 PM EDTEF2Ingham, MI12.050024$75 million
August 2410:19 PM EDTEF0Wayne, MI1.7200$100,000
August 2410:23 PM EDTEF1Wayne, MI3.0200$60,000
August 2410:38 PM EDTEF1Monroe, MI4.9200$1.0 million
August 2410:39 PM EDTEF1Monroe, MI5.4200$350,000
August 2410:43 PM EDTEF1Wayne, MI1.4300$50,000
August 2411:08 PM EDTEF1Sandusky, OH4.5100$35,000
August 2411:46 PM EDTEF1Erie, OH0.3100$30,000
August 2411:59 PM EDTEF1Cuyahoga, OH0.8150$165,000
August 2412:00 AM EDTEF0Lorain, OH0.350$50,000
August 2412:05 AM EDTEF0Lorain, OH1.1100$40,000
August 2412:06 AM EDTEF1Lake, OH3.3150$200,000
August 2412:07 AM EDTEF2Cuyahoga, OH1.5100$300,000
August 2412:11 AM EDTEF1Medina, OH1.5200$20,000
August 2412:16 AM EDTEF1Geauga, OH1.8100$85,000
August 2412:18 AM EDTEF1Geauga, OH1.2175$50,000
August 2412:22 AM EDTEF2Geauga, OH0.7100$65,000
August 2412:35 AM EDTEF0Trumbull, OH1.9100$35,000

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.