Tornadoes · United States · North Dakota · 2010

EF0 tornado, Sweet Briar, North Dakota, August 2, 2010

This EF0 tornado ran 0.2 miles across Morton County on August 2, 2010, touching down at 2:36 PM CDT and reaching 20 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 2, 2010
Touchdown
2:36 PM CDT (19:36 UTC)
Lifted
2:37 PM CDT (19:37 UTC)
On the ground
1 minutes
Path length
0.2 miles (0.3 km)
Path width
20 yards (18 m)
Deaths
0
Injuries
0
County
Morton County
Touchdown point
46.900, -101.140
Lift-off point
46.899, -101.137
Record number
1008021336-01

What the Weather Service recorded

The combination of a short wave trough over central Montana, and a weak instability axis stretched from northwest to southeast across central North Dakota, resulted in scattered severe thunderstorms over portions of central North Dakota during the afternoon hours of Monday, August 2nd. ||Two severe thunderstorm warnings and two tornado warnings were issued. Numerous reports of large hail, several reports of severe thunderstorm winds, several reported funnel clouds, and one confirmed tornado occurred during this episode.

The public reported that a brief tornado touched down in the open country near Crown Butte Dam. No structures were impacted so no damage was done.

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

The warnings

0 minutes of warning. NWS BIS issued a tornado warning for this county at 19:36 UTC, 0 minutes before the tornado touched down, in force until 20:00 UTC.

Issued (UTC)ExpiredProductOffice
01:52 UTC02:30 UTCTornado WarningBIS
02:26 UTC03:13 UTCSevere Thunderstorm WarningBIS
19:36 UTC20:00 UTCTornado WarningBIS
19:58 UTC20:30 UTCTornado WarningBIS
20:22 UTC21:15 UTCSevere Thunderstorm WarningBIS
20:32 UTC22:26 UTCFlood AdvisoryBIS

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 General Thunderstorms Risk. The outlook in force was issued at 16:33 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, 36 km from the path. August 2, 2010.

Skew-T log-pSkew-T log-p diagram, Bismarck Municip, ND at 12:00Z on 2010-08-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 285 joules per kilogram, CIN -191, lifted condensation level 1501 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, Bismarck Municip, ND at 12:00Z on 2010-08-02The 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 -5 square meters per square second, 0 to 6 km bulk shear 24 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
285 J/kg
Mixed-layer CIN
-191 J/kg
Surface CAPE
51 J/kg
Mixed-layer LCL
1501 m above ground
0-6 km bulk shear
24 kt
0-1 km bulk shear
15 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
32 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2
0-3 km lapse rate
4.4 K/km

Open this sounding in Storm Lab

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

4.4 hours after it, 36 km from the path. August 3, 2010.

Skew-T log-pSkew-T log-p diagram, Bismarck Municip, ND at 00:00Z on 2010-08-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 404 joules per kilogram, CIN -120, lifted condensation level 1626 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, Bismarck Municip, ND at 00:00Z on 2010-08-03The 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 12 square meters per square second, 0 to 6 km bulk shear 55 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
404 J/kg
Mixed-layer CIN
-120 J/kg
Surface CAPE
1527 J/kg
Mixed-layer LCL
1626 m above ground
0-6 km bulk shear
55 kt
0-1 km bulk shear
22 kt
0-1 km storm-relative helicity
12 m²/s²
0-3 km storm-relative helicity
135 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4
0-3 km lapse rate
7.3 K/km

Open this sounding in Storm Lab

The radar

The Bismarck radar (KBIS), 32 km away, was scanning. The volume nearest the touchdown began at 19:35 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
19:33 UTCHAIL 1BismarckBurleigh, NDNORTH BISMARCK.
19:33 UTCHAIL 1MandanMorton, ND
19:36 UTCTORNADO3 Nw Crown Butte LakeMorton, NDMULTIPLE FUNNEL REPORTS WITH A BRIEF TOUCH DOWN.
20:03 UTCFUNNEL CLOUD2 W MandanMorton, NDSPOTTER REPORTED THAT THE FUNNEL HAD NOT TOUCHED THE GROUND. SPOTTER CONTINUES TO WATCH IT.
20:14 UTCTSTM WND GST 663 Nw MandanMorton, NDHAIL IN ADDITION TO THE WIIND. DAMAGE TO SIDING AND PLANTS.
20:15 UTCFUNNEL CLOUD1 W MandanMorton, NDFUNNEL CLOUD REPORTED BY LAW ENFORCEMENT.
20:16 UTCTSTM WND GST 701 W MandanMorton, NDSEVEN SEAS MANDAN. OFF DUTY NWS EMPLOYEE.
20:16 UTCNON-TSTM WND GST 701 W MandanMorton, NDSEVEN SEAS MANDAN. OFF DUTY NWS EMPLOYEE.
20:24 UTCHAIL 1MandanMorton, NDOFF DUTY NWS EMPLOYEE...SUNSET DRIVE MANDAN NEAR SEVEN SEAS.
20:25 UTCTSTM WND GST 701 W BismarckBurleigh, NDAT BISMARCK STATE COLLEGE. DIME SIZED HAIL AND VERY HEAVY RAIN AS WELL.
20:25 UTCHAIL 1MandanMorton, NDSOUTHWEST MANDAN.
20:30 UTCHAIL 1MandanMorton, NDSOUTH MANDAN.
20:35 UTCHAIL 1BismarckBurleigh, NDNORTH BISMARCK.
20:36 UTCHAIL 1.75E MandanMorton, NDEAST MANDAN ON MAIN AVENUE. OFF DUTY NWS EMPLOYEE.
20:38 UTCHEAVY RAIN 0BismarckBurleigh, NDMINOR STREET FLOODING NORTH BISMARCK WASHINGTON AND CENTURY INTERSECTION.
20:40 UTCTSTM WND GST 65N BismarckBurleigh, NDALSO HAS NICKEL SIZE HAIL. NORTH SIDE OF BISMARCK.
20:40 UTCNON-TSTM WND GST 65N BismarckBurleigh, NDALSO GETTING NICKEL SIZE HAIL. NO FUNNEL CLOUDS VISIBLE BUT VISION IS OBSCURED.

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

This ground now

The live radar over the trackEvery 2010 tornado in North DakotaEvery tornado in North Dakota since 1950Warnings in force in North Dakota 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.