Aberdeen, SD

Weather Forecast Office

Summary of the August 26-28, 2020 Severe Weather

Overview

Severe thunderstorms impacted parts of central and eastern South Dakota on the evening of August 26, 2020 and again during the evening of August 27 and into the early morning hours of August 28, 2020.

During the afternoon of August 26, supercell thunderstorms developed in western SD and produced numerous reports of hail exceeding the size of golf balls. The largest hailstone reported was the size of a baseball (2.75" in diameter) near Sansarc in Stanley County, SD.

The next evening, another round of severe thunderstorms developed in western South Dakota during the evening of the 27th before traveling east across all of South Dakota into the early morning hours on the 28th. As the storms became more organized they produced strong straight-line winds as well as brief tornados. Numerous reports of straight-line winds over 70 mph were documented along with a peak wind gust of 104 mph. Six tornados also occurred in total. The severe winds along with the tornados damaged trees, buildings, campers, and crops.

Storm Reports from August 26-28, 2020 (orange dots represent heavy rain and/or flooding reports)


Hail in Eagle Butte, SD on August 26, 2020 (Photo by Grady Kraft)	Tornado path through a corn field on the east side of Redfield, SD (Spink County EM & Planning and Zoning)	Surface weather map at 10pm on the 27th

Tornado
August 26
August 27-28
Rainfall

Tornadoes:

Tornado #1: 1 ESE Redfield
Spink County

Date	8/28/2020
Time (Local)	12:56 AM to 1:00 AM
EF Rating	EF-1
Est. Peak Winds	100 mph
Path Length	2.8 miles
Max Width	40 yards
Injuries/Deaths	0
Summary: A tornado touched down on the east side of Redfield, SD in the early morning hours Friday. First indications of damage occurred in a corn field west of 386th Ave. Damage was then noted on East 8th Ave where several vehicles had windows damaged and a trailer was flipped into a corn field across the street. Trees along the property line with Farmers Meat Processing were damaged, one tree having landed facing to the west. Farmers Meat Processing signage was also torn out of the ground. The tornado path became clearly evident in the corn field across East 12th Ave. The tornado then traveled northeast into the Blume Seed building which lost the west side doors and suffered significant wall damage, with the north wall destroyed. Seed silos on the west side of the building also buckled. The tornado spread debris from the Blume Seed building northeast into an adjacent grass field. A tree on the northeast side of this grass field toppled to the north with tree debris extending across US HWY 212. The circulation from the tornado persisted through several soybean and corn fields and resulted in tree damage near 387th Ave. The final crop damage was noted in a bean field north of 172nd St.

Track Map


Radar image from the Sioux Falls radar showing a rotating thunderstorm moving through Redfield, SD	Tornado path through a corn field on the east side of Redfield, SD (Spink County EM & Planning and Zoning)	Tornado path through a corn field on the east side of Redfield, SD (Spink County EM & Planning and Zoning)	Tornado path approaching building on the east side of Redfield, SD (Spink County EM & Planning and Zoning)


Damaged storage bins (Nancy Blume)	Building damage on east side of Redfield, SD (Nancy Blume)	Corner of a building damaged on east side of Redfield, SD (Nancy Blume)	Tornado damaged trees before crossing US 212 and moving through cattails on the east side of Redfield, SD (Spink County EM & Planning and Zoning)


Tornado track starting in corn field on southeast side of Redfield (Photo by Steve Fleegel)	Tornado tracks in corn field on northeast side of Redfield and looking southwest. Tornado #1 is on the right and tornado #2 is on the left. (Photo by Steve Fleegel)	Tornado tracks in corn field on northeast side of Redfield and looking southeast. Tornado #1 is farther away and tornado #2 is on the bottom. (Photo by Steve Fleegel)	Tornado tracks in bean field on northeast side of Redfield and looking north. Tornado #1 is on the right and tornado #2 is on the left. (Photo by Steve Fleegel)

Tornado #2: 2 E Redfield
Spink County

Date	8/28/2020
Time (Local)	12:56 AM to 1:00 AM
EF Rating	EF-0
Est. Peak Winds	85 mph
Path Length	1.8 miles
Max Width	40 yards
Injuries/Deaths	0
Summary: The tornado track started 2 miles east of Redfield near SD HWY 212. The track was evident through multiple corn fields, with corn completely leveled in some spots. The tornado crossed 172nd ST and traveled through a bean field before dissipating.

Track Map

Track Map EF-Scale


Coming soon	Coming soon	Coming soon	Coming soon

Tornado #3: 5 WNW Clear Lake
Deuel County

Date	8/28/2020
Time (Local)	2:11 AM to 2:13 AM
EF Rating	EF-1
Est. Peak Winds	100 mph
Path Length	0.92 miles
Max Width	40 yards
Injuries/Deaths	0
Summary: A brief tornado touchdown destroyed the roof and severely damaged walls of a hog barn 5 miles WNW of Clear Lake near 180th St. Debris from the roof was tossed a quarter mile to the north across the highway. Debris was also lodged in hay bales and hay bales were damaged and missing net wrap.

Track Map


Drone image of destroyed hog barn, courtesy of the Deuel County Sheriff's Office & Codington County Search & Rescue	Significant property damage, image from damage survey	Significant property damage, image from damage survey	Significant property damage, image from damage survey

Tornado #4: 6 W Clear Lake
Deuel County

Date	8/28/2020
Time (Local)	2:09 AM to 2:10 AM
EF Rating	EF-0
Est. Peak Winds	85 mph
Path Length	0.1 miles
Max Width	20 yards
Injuries/Deaths	0
Summary: A very brief tornado touched down in a small corn plot 6 miles west of Clear Lake just south of 182nd St. Corn was completely flattened with a distinct convergent pattern. Some tree limb damage was also noted.

Track Map


Brief Track Visible in Corn - NWS Damage Survey	Brief Track Visible in Corn - NWS Damage Survey

Tornado #5: 6 W Clear Lake
Deuel County

Date	8/28/2020
Time (Local)	2:09 AM to 2:10 AM
EF Rating	EF-0
Est. Peak Winds	85 mph
Path Length	0.78 miles
Max Width	30 yards
Injuries/Deaths	0
Summary: A very brief tornado touched down causing mainly tree damage at a residence. Large tree branches were broken and a few trees uprooted. Some minor damage was also done to sheet metal on a small outbuilding. The track continued north of the residence, roughly one half mile through a corn field.

Track Map


Tree Damage - NWS Damage Survey	Tree damage and minor outbuilding damage - NWS Damage Survey	Tree Damage - drone image courtesy of the Deuel County Sheriff's Office & Codington County Search & Rescue	Path visible in corn north of residence - drone image courtesy of the Deuel County Sheriff's Office & Codington County Search & Rescue

Tornado #6: 9 SW Clear Lake
Deuel County

Date	8/28/2020
Time (Local)	2:08 AM to 2:09 AM
EF Rating	EF-0
Est. Peak Winds	85 mph
Path Length	0.1 miles
Max Width	50 yards
Injuries/Deaths	0
Summary: A very brief tornado touched down in farm yard. One small shed was completely destroyed, pulling the anchor posts out of the ground. One hay shed roof was destroyed and was tossed into the side of the barn. The barn lean-to roof was partially damaged as well.

Track Map


Property damage - drone image courtesy of the Deuel County Sheriff's Office & Codington County Search & Rescue	Property damage - drone image courtesy of the Deuel County Sheriff's Office & Codington County Search & Rescue	Property damage - drone image courtesy of the Deuel County Sheriff's Office & Codington County Search & Rescue	Property damage - drone image courtesy of the Deuel County Sheriff's Office & Codington County Search & Rescue

EF0 Weak 65-85 mph	EF1 Moderate 86-110 mph	EF2 Significant 111-135 mph	EF3 Severe 136-165 mph	EF4 Extreme 166-200 mph	EF5 Catastrophic 200+ mph

The Enhanced Fujita (EF) Scale classifies tornadoes into the following categories:

August 26, 2020:

Find below a few images of the significant hail that fell across portions of central SD.


Storm reports from August 26, 2020 (SPC)	Hail in Eagle Butte, SD (Photo from Tonya White Bull)	Hail in Eagle Butte, SD (Photo from Tonya White Bull)	Timber Lake, SD hail (Photo by Kyle Nelson)


Hail in Timber Lake, SD (Photo by Lauren Kraft)	Radar loop of the supercell thunderstorms that produced hail up to baseballs.	Potential large hail areas

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE ABERDEEN SD
1108 AM CDT THU AUG 27 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0548 PM     HAIL             6 SW SANSARC            44.46N 101.13W
08/26/2020  E2.75 INCH       STANLEY            SD   PUBLIC           
            TIME ESTIMATED. BROKE 6 WINDOWS ON NORTH AND 
            WEST SIDE OF RESIDENCE. 

0513 PM     TSTM WND GST     10 SW CHANTLER CREEK RE 44.39N 100.77W
08/26/2020  M53 MPH          STANLEY            SD   MESONET          
            MESONET STATION 202 HAYES (SDDOT). 

0445 PM     HAIL             8 ENE SANSARC           44.56N 100.89W
08/26/2020  E1.50 INCH       STANLEY            SD   PUBLIC           
            TIME ESTIMATED. 

0420 PM     TSTM WND DMG     9 N SANSARC             44.64N 101.05W
08/26/2020                   STANLEY            SD   PUBLIC           
            ROOF TORN OFF ONE OUTBUILDING, A SECOND 
            OUTBUILDING HAD NORTH DOOR BLOWN IN. TIME 
            ESTIMATED. 

0420 PM     HAIL             9 N SANSARC             44.64N 101.05W
08/26/2020  E1.00 INCH       STANLEY            SD   PUBLIC           
            TIME ESTIMATED. 

0417 PM     TSTM WND GST     13 NNW SANSARC          44.67N 101.14W
08/26/2020  M70 MPH          STANLEY            SD   MESONET          
            MESONET STATION 168 FOSTER BAY (SDDOT). 

0725 PM     HAIL             6 SSE OKATON            43.80N 100.87W
08/26/2020  E1.25 INCH       JONES              SD   PUBLIC           
            TIME ESTIMATED. 

0620 PM     HAIL             1 N TIMBER LAKE         45.44N 101.07W
08/26/2020  E2.00 INCH       DEWEY              SD   PUBLIC           
            REPORT OF GOLFBALL AND LARGER. 

0617 PM     HAIL             TIMBER LAKE             45.43N 101.07W
08/26/2020  E2.00 INCH       DEWEY              SD   PUBLIC           
            UPDATE TO PREVIOUS REPORT. 

0613 PM     HAIL             TIMBER LAKE             45.43N 101.07W
08/26/2020  E1.75 INCH       DEWEY              SD   PUBLIC           
            RELAYED THROUGH SPOTTER. 

0613 PM     TSTM WND GST     TIMBER LAKE             45.43N 101.08W
08/26/2020  E60 MPH          DEWEY              SD   PUBLIC           
            RELAYED THROUGH SPOTTER. 

0558 PM     HAIL             5 E WHITE HORSE         45.28N 100.79W
08/26/2020  E1.00 INCH       DEWEY              SD   PUBLIC           
            TIME ESTIMATED. 

0525 PM     HAIL             7 SSE ISABEL            45.30N 101.38W
08/26/2020  E0.88 INCH       DEWEY              SD   PUBLIC           
            LARGEST WAS NICKLES, TIME ESTIMATED. 

0430 PM     HAIL             5 NW PARADE             45.08N 101.16W
08/26/2020  E1.75 INCH       DEWEY              SD   PUBLIC           
            TIME ESTIMATED. MULTIPLE SIZES BUT LARGEST 
            WAS GOLF BALL. COVERED GROUND. 

0406 PM     HAIL             EAGLE BUTTE             45.00N 101.24W
08/26/2020  E1.75 INCH       DEWEY              SD   TRAINED SPOTTER  
            UPDATE TO PREVIOUS REPORT. 

0402 PM     HAIL             EAGLE BUTTE             45.00N 101.25W
08/26/2020  E1.25 INCH       DEWEY              SD   TRAINED SPOTTER  
            SLIGHTLY LARGER THEN QUARTERS. 

0630 PM     TSTM WND GST     11 S BULLHEAD           45.61N 101.06W
08/26/2020  M59 MPH          CORSON             SD   MESONET          
            MESONET STATION GRRS2 BULLHEAD 10 S. 
            ESTIMATED TIME.

August 27-28, 2020

The severe thunderstorms that moved through central and eastern South Dakota during the late evening of the 27th and early morning of the 28th produced numerous wind gusts over 70 mph and caused damage to several outbuildings and trees.


Storm reports from August 27-28, 2020 (SPC)	Listing of highest measured wind gusts	Snapped power pole 4 miles WSW of Ames, SD, courtesy of Brad and Jolene Haun	Property damage 4 miles WSW of Ames, SD, courtesy of Brad and Jolene Haun


Trailer damage from straight-line winds in Fort Pierre, courtesy of Brooke Mentele	Trailer damage from straight-line winds in Fort Pierre, courtesy of Brooke Mentele	Damage at Lake Poinsett. Photo courtesy of Vickie Barthel	Damage at Lake Poinsett. Photo courtesy of Vickie Barthel


Positive and negative lightning strikes from the event, from Vaisala's US National Lightning Detection Network	Radar loop of the storms that crossed South Dakota on August 27-28, 2020

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE ABERDEEN SD
529 PM CDT FRI AUG 28 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1101 PM     TSTM WND GST     1 E HAYES               44.37N 101.00W
08/27/2020  M104 MPH         STANLEY            SD   PUBLIC           
            PERSONAL WEATHER STATION. 

1100 PM     TSTM WND GST     2 ENE BUNKER            44.25N 101.06W
08/27/2020  M97 MPH          STANLEY            SD   PUBLIC           
            PERSONAL WEATHER STATION. RADAR ESTIMATED 
            TIME AND APPROXIMATE LOCATION. 

1114 PM     TSTM WND GST     10 SW CHANTLER CREEK RE 44.39N 100.77W
08/27/2020  M91 MPH          STANLEY            SD   MESONET          
            MESONET STATION 202 HAYES (SDDOT). 

1058 PM     TSTM WND GST     5 W HAYES               44.37N 101.12W
08/27/2020  M80 MPH          STANLEY            SD   PUBLIC           
            PEAK GUST FOR THIS PERSONAL WEATHER STATION. 

1055 PM     TSTM WND GST     5 W HAYES               44.37N 101.12W
08/27/2020  M78 MPH          STANLEY            SD   PUBLIC           
            PERSONAL WEATHER STATION. 

1143 PM     TSTM WND GST     4 WSW BLUNT             44.50N 100.07W
08/27/2020  M75 MPH          HUGHES             SD   MESONET          
            RWIS. 

1135 PM     TSTM WND GST     2 ENE PIERRE            44.38N 100.29W
08/27/2020  M72 MPH          HUGHES             SD   ASOS             

1109 PM     TSTM WND GST     8 ESE HAYES             44.33N 100.87W
08/27/2020  M71 MPH          STANLEY            SD   PUBLIC           
            PERSONAL WEATHER STATION. 

1220 AM     TSTM WND GST     4 WSW AMES              44.24N 99.15W
08/28/2020  E70 MPH          HAND               SD   PUBLIC           
            DAMAGE TO OUTBUILDINGS, FENCING AND CROPS. 
            TIME AND WIND SPEEDS ESTIMATED. 

1100 PM     TSTM WND GST     13 NNW SANSARC          44.67N 101.14W
08/27/2020  M68 MPH          STANLEY            SD   MESONET          
            RWIS. 

1204 AM     TSTM WND GST     HOLABIRD                44.52N 99.60W
08/28/2020  M68 MPH          HYDE               SD   PUBLIC          
            PERSONAL WEATHER STATION. 

1139 PM     TSTM WND GST     8 ENE GREY GOOSE        44.54N 100.19W
08/27/2020  M68 MPH          HUGHES             SD   PUBLIC           
            PERSONAL WEATHER STATION. 

0213 AM     TSTM WND GST     7 NE ESTELLINE          44.66N 96.82W
08/28/2020  M67 MPH          DEUEL              SD   MESONET          
            MESONET STATION 47 BRANDT (SDDOT). 

1123 PM     TSTM WND GST     1 S OKOBOJO CREEK REC A 44.59N 100.46W
08/27/2020  M62 MPH          SULLY              SD   PUBLIC           
            PERSONAL WEATHER STATION. RADAR ESTIMATED 
            TIME. 

0155 AM     TSTM WND GST     3 WNW STONE BRIDGE      44.62N 97.11W
08/28/2020  M61 MPH          HAMLIN             SD   PUBLIC           
            PERSONAL WEATHER STATION. 

1152 PM     TSTM WND GST     3 SE RELIANCE           43.85N 99.56W
08/27/2020  M58 MPH          LYMAN              SD   MESONET          
            MESONET STATION 54 RELIANCE (SDDOT). 

1241 AM     TSTM WND GST     6 E DANFORTH            44.24N 98.77W
08/28/2020  M58 MPH          HAND               SD   MESONET          
            RWIS. 

1130 PM     TSTM WND DMG     FORT PIERRE             44.36N 100.38W
08/27/2020                   STANLEY            SD   PUBLIC           
            TRAILER ROLLED AND DESTROYED. TIME AND 
            LOCATION ARE APPROXIMATE. PHOTO VIA SOCIAL 
            MEDIA. 

1130 PM     TSTM WND DMG     1 SSW OVERLOOK REC AREA 44.44N 100.39W
08/27/2020                   STANLEY            SD   EMERGENCY MNGR   
            TREES DOWN. APPROXIMATE LOCATION AND TIME. 

0100 AM     TORNADO          1 E REDFIELD            44.87N 98.50W
08/28/2020                   SPINK              SD   EMERGENCY MNGR   
            DAMAGE TO BUILDING WAS CONFIRMED TO BE A 
            TORNADO, WITH ADDITIONAL EVIDENCE FOR A 
            CIRCULATION IN AN ADJACENT CORN FIELD. THIS 
            IS AN UPDATE TO THE PREVIOUS REPORT OF WIND 
            DAMAGE. TIME IS ESTIMATED. 

0100 AM     TSTM WND DMG     1 ESE REDFIELD          44.87N 98.50W
08/28/2020                   SPINK              SD   PUBLIC           
            STRUCTURAL DAMAGE TO AGRICULTURAL BUSINESS 
            BUILDING AND STORAGE SILOS. TIME ESTIMATED. 

0100 AM     TSTM WND DMG     2 E REDFIELD            44.88N 98.49W
08/28/2020                   SPINK              SD   EMERGENCY MNGR   
            2 FOOT DIAMETER TREE DOWN. ESTIMATED TIME 
            AND APPROXIMATE LOCATION. 

0150 AM     TSTM WND DMG     4 ESE LAKE NORDEN       44.55N 97.14W
08/28/2020                   HAMLIN             SD   PUBLIC           
            MINOR DAMAGE TO AWNINGS ON CAMPERS, TENTS 
            KNOCKED DOWN. VIA SOCIAL MEDIA. TIME 
            ESTIMATED. 

0145 AM     TSTM WND DMG     4 W HAYTI               44.66N 97.29W
08/28/2020                   HAMLIN             SD   EMERGENCY MNGR   
            ROOF BLOWN OFF BUS BARN, DAMAGE TO DAYCARE 
            ROOF. ADDITIONAL TREE DAMAGE NOTED IN TOWN 
            OF HAYTI. TIME IS ESTIMATED. 

0222 AM     TSTM WND DMG     4 E ASTORIA             44.55N 96.46W
08/28/2020                   DEUEL              SD   PUBLIC           
            SEVERAL TREES EITHER DAMAGED OR KNOCKED 
            DOWN, CALLER THINKS ITS STRAIGHT LINE WIND 
            DAMAGE. TIME IS ESTIMATED. 

0220 AM     TSTM WND DMG     2 ESE ASTORIA           44.55N 96.51W
08/28/2020                   DEUEL              SD   PUBLIC           
            NUMEROUS TREES DAMAGED OR KNOCKED OVER, 
            APPEARS TO BE STRAIGHT LINE DAMAGE. TIME 
            ESTIMATED.

Rain Reports

Rainfall estimates from 9am August 26 to 9am August 28, 2020.

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