Tornadoes · United States · Minnesota · 2018
EF0 tornado, Bombay to Bellechester, Minnesota, September 20, 2018
From Bombay to Bellechester, this EF0 tornado ran 6.2 miles across Goodhue and Wabasha counties on September 20, 2018, touching down at 7:09 PM CDT and reaching 150 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.
EF065 to 85 mphthis tornado
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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 20, 2018
- Touchdown
- 7:09 PM CDT (00:09 UTC)
- Lifted
- 7:14 PM CDT (00:14 UTC)
- On the ground
- 5 minutes
- Path length
- 6.2 miles (10.0 km)
- Path width
- 150 yards (137 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $50,000
- Crop damage
- $5,000
- Counties
- Goodhue and Wabasha counties
- Touchdown point
- 44.335, -92.651
- Lift-off point
- 44.369, -92.534
- Record number
- 1809201809-01
The damage survey
16 damage points were recorded along this path by NWS MPX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 85 mph.
- Path through corn began just south of house based on video of damage. Few branches were downed at the house.
- No structural damage to farm directly from the wind, although several large branches from some trees were blown and pierced the roof of a large machine shed.
- few trees down. corn path.
- Grain bin also blown over.
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
A violent outbreak of significant straight line winds, downburst winds, and multiple tornadoes occurred during the afternoon and early evening across southern Minnesota. ||During the afternoon of Thursday, September 20th, a warm front lifted northward across far southern Minnesota. By the late afternoon, the warm front lied from just south of the Minnesota River, northeast to around the city of Wabasha. ||Several thunderstorms developed in southwest Minnesota, and northwest Iowa. These storms moved into far southern Minnesota and quickly intensified and raced off to the east-northeast along, and north of this warm front. ||Damage reports started to come into the office around 4 PM CST in Martin County, with multiple reports of significant damage from south of Mankato, to Waseca, then northeast through Waterville, Morristown, Owatonna, Faribault, Northfield, Cannon Falls, and Red Wing before moving into west central Wisconsin. ||A long, and several day storm survey indicated at least XX confirmed tornadoes occurred in a widespread area of damaging winds from Martin County, northeast into west central Wisconsin. ||The most destruction part of the storm occurred around Waterville, Morristown, Owatonna, Faribault and Cannon Falls. These cities all reported homes, buildings and warehouses either damaged or destroyed. ||Hundreds of large, mature trees were uprooted or snapped along this path of destruction, including numerous trees up to 4 feet in diameter. In addition to the trees, structural damage was widespread including the Faribault airport where 80 planes were either damaged or destroyed as hangers were blown off their foundation. ||The towns of Waterville and Faribault had the most homes damaged which was associated with EF2 tornado damage. ||Two miles west of the Faribault airport, a resort area on Roberds Lake had upwords of 75 percent of the trees uprooted or blown down on the east side of the lake. Some of the trees landed on homes and split them in half.
A line of thunderstorms moved across southeast Minnesota during the evening of September 20th. These storms produced a tornado that briefly moved across the far northwest corner of Wabasha County north of Mazeppa. The storms also occasionally produced some damaging winds with trees blown down west of West Concord (Dodge County) and in Lake City (Wabasha County).
A NWS storm survey, plus areal footage of drone and satellite data, concluded that an EF0 tornado tracked east of Kenyon, then northeast for 8.2 miles before lifting west of Zumbrota. This tornado tracked mainly through corn and soy bean fields, and occasionally damaged a few sheds and outbuildings. The damage was consistent with EF0 damage with maximum wind speeds of 75 mph and a width of 250 yards.
A NWS storm survey, plus areal footage of drone and satellite data, concluded that an EF0 tornado started north of Zumbrota, and tracked northeast for 5.4 miles until moving into Wabasha County, southwest of Bellechester. This tornado tracked mainly through corn and soy bean fields, and occasionally damaging a few sheds and outbuildings. The damage was consistent with EF0 damage with maximum wind speeds of 85 mph and a width of 150 yards.
This the continuation of a tornado that began in Goodhue County. A NWS Storm Survey team found that the tornado moved briefly across the far northwest corner of Wabasha County north of Mazeppa before moving back into Goodhue County. Damage was limited to crops.
This is the continuation of the Goodhue-Wabasha County tornado that tracked briefly into Wabasha County, before moving back into Goodhue County, and dissipated approximately 3/4 of a mile west of Bellechester. Areal footage of drone, satellite data and a storm survey, indicated EF0 damage in a corn field.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The forecast that day
The Storm Prediction Center had this point in a Enhanced Risk, with a 0.10 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 19:49 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.
What forecasters said that day
The local office's own words before the tornado touched down, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Twin Cities, MN wrote its last area forecast discussion before the tornado touched down at Sep 20, 6:56 PM CDT, 13 minutes earlier.
Area forecast discussion, Sep 20, 6:56 PM CDT, 13 minutes before
Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 656 PM CDT Thu Sep 20 2018 .UPDATE... Issued at 639 PM CDT Thu Sep 20 2018 Updated to include 00z aviation discussion below. && .SHORT TERM...(This evening through Friday) Issued at 250 PM CDT Thu Sep 20 2018 Elevated thunderstorms developed along the moisture gradient across Southwestern and Central MN with heavy rain and wind gusts near 30- 35 kts. Clearing and an increase in MUCAPE has been noticed across South Central MN. This clearing trend is expected to continue through the early afternoon and help destabilized the boundary layer with near 3000 J/kg of SBCAPE expected by 21Z (according to the RAP). The surface low will continue to deepen as it progresses northeastward with its placement over the NE/IA/SD border at 1930Z. An Enhanced Risk of Severe Weather remains in place due to the concern for severe wind, tornado, and hail during the late afternoon and evening. Thunderstorms are expected to develop along a cold front with the main mode being linear. However, a few isolated cells could develop ahead of this line. Bulk shear is expected to be near 60 kts by 00Z across Southern MN and Western WI as 850 mb winds increase to 50 kts. LCL values are expected to be near 1000 m and DCAPE will be near 1300 J/kg, so severe winds will be possible along the cold front. SFC to 1 km shear will be near 30-40 kts which is supports the tornado potential. Storms are expected to exit to the east overnight by 06Z with cold air advection to follow. Winds will be windy with gusts near 25-30 kts common Friday morning. .LONG TERM...(Friday night through Thursday) Issued at 250 PM CDT Thu Sep 20 2018 Surface high pressure will be in place to start the long term period, which will make for a cool start to Saturday morning. With light winds and clear skies, expect lows to dip into the mid 30s from parts of central MN across west central WI. Therefore areas north of I-94 will have the potential for the first frost of the season. High pressure prevails through the weekend and brings quiet and dry weather, with highs in the 60s on Saturday. Temps moderate a tad on Sunday as the high pressure begins to shift southeast and southerly flow develops. Expect highs in the mid 60s to lower 70s. Monday and Monday night there is decent agreement amongst the models that a decent shortwave trough will move across the north central CONUS and push a front across the area. Have included high chance POPs. Behind this system temperatures cool down slightly below normal, with highs in the 60s and lows in the 40s. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 639 PM CDT Thu Sep 20 2018 Complicated next 6-12 hours due to ongoing convection pushing thru eastern/southern MN through western WI followed by low stratus and wind shifts behind the convection. Have included wind gusts up to 50kt in advance of the convection as reports have been coming in indicating wind speeds in the 50-60kt range. Ceilings may be a bit tricky in advance of and with the line of convection then subsidence in its wake will drop ceilings to IFR for much of the late evening through the overnight hours. Steady improvement expected tomorrow as the cold front exits and high pressure arrives. Breezy/gusty winds will continue as wind directions eventually go to SW and W behind the front. Ceilings will gradually break with at least partially clear skies late tomorrow afternoon into tomorrow evening. KMSP...Strong winds/heavy precip to start as the line of storms moves through right around initialization time. Ceilings then to drop through the MVFR range to IFR overnight through daybreak. Sub-1700ft ceilings likely for at least the first half of the day tomorrow before VFR conditions take hold for the afternoon/evening push. /OUTLOOK FOR KMSP/ Sat...VFR. Wind SW 5-10 kts. Sun...VFR. Wind SE 5-10 kts. Mon...Mainly VFR. Chc MVFR/TSRA late. Winds S 10-20 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && UPDATE...JPC SHORT TERM...AMK LONG TERM...LS AVIATION...JPC
Hazardous weather outlook, Sep 20, 10:21 AM CDT, 8 hours 48 minutes before
Hazardous Weather Outlook National Weather Service Twin Cities/Chanhassen MN 1021 AM CDT Thu Sep 20 2018 MNZ051>053-058>063-065>070-073>078-082>085-091>093-WIZ014>016- 023>028-211530- Sherburne-Isanti-Chisago-Meeker-Wright-Hennepin-Anoka-Ramsey- Washington-Renville-McLeod-Sibley-Carver-Scott-Dakota-Redwood- Brown-Nicollet-Le Sueur-Rice-Goodhue-Watonwan-Blue Earth-Waseca- Steele-Martin-Faribault-Freeborn-Polk-Barron-Rusk-St. Croix- Pierce-Dunn-Pepin-Chippewa-Eau Claire- 1021 AM CDT Thu Sep 20 2018 This Hazardous Weather Outlook is for portions of central Minnesota...east central Minnesota...south central Minnesota... southeast Minnesota...southwest Minnesota...northwest Wisconsin and west central Wisconsin. .DAY ONE...Today and Tonight Severe thunderstorms are possible this afternoon in south central and east central Minnesota, as well as in west central Wisconsin. The primary risk will be strong winds. Large hail and heavy rain will also be possible, along with a few tornadoes. .DAYS TWO THROUGH SEVEN...Friday through Wednesday There is a chance of thunderstorms on Monday. .SPOTTER INFORMATION STATEMENT... SKYWARN spotter activation will likely be needed this afternoon and early evening. MNZ041>045-047>050-054>057-064-211530- Douglas-Todd-Morrison-Mille Lacs-Kanabec-Stevens-Pope-Stearns- Benton-Lac Qui Parle-Swift-Chippewa-Kandiyohi-Yellow Medicine- 1021 AM CDT Thu Sep 20 2018 This Hazardous Weather Outlook is for portions of central Minnesota...east central Minnesota and west central Minnesota. .DAY ONE...Today and Tonight Thunderstorms are possible this afternoon. The threat for severe weather is low. .DAYS TWO THROUGH SEVEN...Friday through Wednesday There is a chance of thunderstorms on Monday. .SPOTTER INFORMATION STATEMENT... SKYWARN spotter activation will not be needed.
In the hours before
Local storm report, Sep 20, 6:44 PM CDT, 25 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
644 PM CDT THU SEP 20 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0636 PM TSTM WND GST 2 W OWATONNA 44.09N 93.26W
09/20/2018 M52 MPH STEELE MN PUBLIC
CORRECTS PREVIOUS TSTM WND GST REPORT FROM 2
W OWATONNA. REPORT RELAYED BY STEELE COUNTY
EM FROM TRAINED SPOTTER.
&&
CTGLocal storm report, Sep 20, 6:47 PM CDT, 22 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
647 PM CDT THU SEP 20 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0646 PM HEAVY RAIN 1 S CAMBRIDGE 45.56N 93.22W
09/20/2018 E4.00 INCH ISANTI MN TRAINED SPOTTER
TRAINED SPOTTER CALLED TO REPORT STREET
FLOODING UP TO THE CURB. NO PHOTO PROVIDED.
&&
CTGLocal storm report, Sep 20, 7:00 PM CDT, 9 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
700 PM CDT THU SEP 20 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0645 PM TSTM WND DMG 3 NW FARIBAULT 44.33N 93.31W
09/20/2018 RICE MN EMERGENCY MNGR
SIGNIFICANT DAMAGE AT FARIBAULT AIRPORT.
PLANES FLIPPED. OTHER DAMAGE REPORTS JUST
COMING IN TO RICE COUNTY EM.
&&
TDKLocal storm report, Sep 20, 7:05 PM CDT, 4 minutes before
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</html>Special weather statement, Sep 20, 7:05 PM CDT, 4 minutes before
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</html>Local storm report, Sep 20, 7:09 PM CDT, 0 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
709 PM CDT THU SEP 20 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0626 PM TSTM WND DMG 5 S WASECA 44.02N 93.49W
09/20/2018 WASECA MN STORM CHASER
STORM CHASER CALLED TO REPORT MULTIPLE 6-12
INCH TREE BRANCHES DOWN. POWER POLE AND 18
INCH PINE TREE ALSO SNAPPED. NO PHOTOS
PROVIDED.
&&
CTGThe 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.
Minneapolis, MN (KMPX), 12:00Z
11.8 hours after it, 97 km from the path. September 21, 2018.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -20964 J/kg
- Surface CAPE
- 43 J/kg
- Mixed-layer LCL
- 608 m above ground
- 0-6 km bulk shear
- 70 kt
- 0-1 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- -68 m²/s²
- 0-3 km storm-relative helicity
- 1 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 5.7 K/km
The surface observations
Red Wing (RGK), 28 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 00:00 UTC |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Minneapolis radar (KMPX), 95 km away, was scanning. The volume nearest the touchdown began at 00:09 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.
This ground now
The live radar over the trackEvery 2018 tornado in MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are
The other tornadoes of September 20, 2018
28 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| September 20 | 2:23 PM EDT | EF1 | Geauga, OH | 3.2 | 25 | $75,000 | ||
| September 20 | 2:31 PM EDT | EF1 | Geauga, OH | 4.1 | 25 | $145,000 | ||
| September 20 | 5:21 PM CDT | EF1 | Dickinson, IA | 5.1 | 35 | |||
| September 20 | 5:52 PM CDT | EF1 | Martin, MN | 6.5 | 220 | $1.5 million | ||
| September 20 | 5:58 PM CDT | EF0 | Blue Earth, MN | 1.1 | 70 | |||
| September 20 | 6:04 PM CDT | EF0 | Blue Earth, MN | 0.8 | 70 | $50,000 | ||
| September 20 | 6:19 PM CDT | EF1 | Waseca, MN | 7.1 | 440 | 1 | ||
| September 20 | 6:20 PM CDT | EF0 | Waseca, MN | 0.7 | 20 | |||
| September 20 | 6:20 PM CDT | EF1 | Waseca, MN | 10.9 | 300 | |||
| September 20 | 6:25 PM CDT | EF1 | Waseca, MN | 7.2 | 330 | |||
| September 20 | 6:28 PM CDT | EF1 | Waseca, MN | 11.1 | 350 | |||
| September 20 | 6:31 PM CDT | EF2 | Rice, MN | 4.9 | 300 | |||
| September 20 | 6:35 PM CDT | EF1 | Steele, MN | 8.1 | 300 | |||
| September 20 | 6:35 PM CDT | EF1 | Rice, MN | 8.6 | 440 | |||
| September 20 | 6:37 PM CDT | EF2 | Rice, MN | 3.0 | 600 | |||
| September 20 | 6:40 PM CDT | EF1 | Rice, MN | 1.6 | 150 | |||
| September 20 | 6:40 PM CDT | EF1 | Rice, MN | 9.1 | 500 | |||
| September 20 | 6:44 PM CDT | EF1 | Rice, MN | 4.7 | 440 | |||
| September 20 | 6:44 PM CDT | EF1 | Rice, MN | 7.2 | 300 | |||
| September 20 | 6:45 PM CDT | EF1 | Rice, MN | 5.8 | 440 | |||
| September 20 | 6:46 PM CDT | EF0 | Rice, MN | 5.5 | 75 | |||
| September 20 | 6:52 PM CDT | EF1 | Rice, MN | 5.3 | 550 | |||
| September 20 | 6:56 PM CDT | EF0 | Goodhue, MN | 8.7 | 250 | $50,000 | ||
| September 20 | 7:01 PM CDT | EF1 | Goodhue, MN | 1.9 | 440 | |||
| September 20 | 7:02 PM CDT | EF0 | Dakota, MN | 3.2 | 70 | $15,000 | ||
| September 20 | 7:04 PM CDT | EF0 | Dakota, MN | 4.6 | 220 | |||
| September 20 | 7:16 PM CDT | EF0 | Pierce, MN to WI | 3.2 | 100 | $5,000 | ||
| September 20 | 7:27 PM CDT | EF0 | Pierce, WI | 1.7 | 140 |
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.