Rapid City, SD

Weather Forecast Office

July 3, 2019 Tornadoes, Severe Weather, and Heavy Rain

Overview

Severe storms with tornadoes, large hail, damaging straight-line winds, heavy rain, and flash flooding moved across northeastern Wyoming and western South Dakota during the afternoon and evening of July 3, 2019. Tornadoes were reported near both Allen, South Dakota, and southwest of Dewey, South Dakota (located across the border in Wyoming). The lightning map to the right shows that there were concentrated areas of cloud-to-ground lightning flashes in both of those areas.

24-h CG lightning ending 6 am July 4th, 2019

24-hour cloud-to-ground lightning from 6 am July 4 to 6 am July 5, 2019

Tornadoes
Rainfall & Flooding
Photos & Video
Radar
Storm Reports
Environment

Tornadoes:

Tornadoes - 8 west-northwest of Swett, 9 west of Allen, 5 west-southwest of Allen, and 3 southwest of Allen
Bennett County

Date	July 3, 2019
Time (Local)	4:06, 4:19, 4:37, and 4:42 to 4:45 pm MDT
EF Rating	Unknown
Est. Peak Winds	Unknown
Path Length	Unknown
Max Width	Unknown
Injuries/Deaths	0
Summary: The first three tornadoes lasted for 1 minute or less. The last tornado lasted at least three minutes, and then it became rain-wrapped so it is uncertain as to how long it lasted. Locations are best estimates based on reports and radar.

Track Map

Tornado - 2 southwest of Dewey
Weston County

Date	July 3, 2019
Time (Local)	4:27 to 4:44 pm MDT
EF Rating	Unknown
Est. Peak Winds	Unknown
Path Length	Unknown
Max Width	Unknown
Injuries/Deaths	0
Summary: Multiple spotters reported a tornado southwest of Dewey, just across the state line in southeastern Weston County in Wyoming. The tornado was "up and down" through 4:44 pm MDT.

Track Map

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

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

Rainfall & Flooding

Heavy rain and flooding was reported over parts of the area. Here are some 24-hour rainfall reports from CoCoRaHS (Community Collaborative Rain, Hail & Snow Network) ending at 7 am on July 4, 2019.

SDBN02    : BATESLAND 7.4 NNE        *   : 2.70 
SDBN17    : MARTIN 14.1 ENE          *   : 2.25 
SDTP28    : WINNER 10.2 NNW          *   : 1.78 
SDBN07    : MARTIN 11.7 E            *   : 1.75 
SDFR24    : EDGEMONT 14.2 NW         *   : 1.62 
SDTP27    : COLOME 9.3 SSW           *   : 1.50 
SDMD32    : PIEDMONT 4.6 E           *   : 1.47 
SDTP07    : HAMILL 1.7 SW            *   : 1.42 
SDFR30    : HOT SPRINGS 4.2 W        *   : 1.42 
SDML10    : NORRIS 2.5 NE            *   : 1.42 
SDMD36    : RAPID CITY 6.2 NNE       *   : 1.39 
SDTP20    : WINNER 0.5 WSW           *   : 1.31 
SDML03    : NORRIS 2.0 SSW           *   : 1.30 
SDHK19    : PHILIP 18.0 N            *   : 1.05 
SDMD31    : TILFORD 0.1 N            *   : 0.95 
SDFR34    : HOT SPRINGS 0.4 NW       *   : 0.95 
SDHK05    : PHILIP 20.7 NW           *   : 0.94 
SDML14    : WHITE RIVER 12.7 ENE     *   : 0.90 
SDLW06    : LEAD 5.5 SSW             *   : 0.88 
SDJK06    : KADOKA 0.3 N             *   : 0.82 
SDLY16    : VIVIAN 5.1 SSW           *   : 0.81 
SDTP13    : DALLAS 13.2 SSW          *   : 0.80 
SDPN56    : RAPID CITY 9.6 WNW       *   : 0.75 
SDPN09    : WALL 13.0 SSE            *   : 0.64 
SDCS27    : HERMOSA 10.3 ESE         *   : 0.57

24-hour estimated rainfall ending 6 am July 4, 2019

24-hour estimated rainfall ending at 6 am MDT on July 4, 2019

Flooding near 3-Mile Creek southwest of Kyle (photo courtesy of Oglala Sioux Tribe EM)

New culvert on Bennett County road South of Swett was washed out by flooding resulting from Wednesday July 3rd tornadic storm heavy rains. 10 ft. diameter culvert installation was just completed on Wednesday. Washed out Thursday morning. pic.twitter.com/yxXjaS9fI3
— Martin Vol Fire Dept (@martin_vol) July 5, 2019

Photos & Video

Below are photos of the storm that produced tornadoes to the west through southwest of Allen, SD. The photos are courtesy of Jennifer Nelson.

Photo of Allen tornadic storm

Below are photos of the storm and tornado that occurred southwest of Dewey, SD (across the state line in far southeastern Weston County, Wyoming). The photos are courtesy of Vince Miller.

Vince Miller photo of supercell before Dewey tornado

Vince Miller photo #1 of tornado southwest of Dewey

Vince Miller photo #2 of tornado southwest of Dewey

Vince Miller photo #3 of tornado southwest of Dewey

Below are photos of the storm and tornado that occurred southwest of Dewey, SD (across the state line in far southeastern Weston County, Wyoming). The photos are courtesy of Brandon Bailey.

Brandon Bailey photo of supercell before Dewey tornado

Brandon Bailey photo #1 of tornado southwest of Dewey

Brandon Bailey photo #2 of tornado southwest of Dewey

Brandon Bailey photo #3 of tornado southwest of Dewey

Below are photos of hail as the storm moved over Antelope Ridge in the Box Elder, SD, area. The photos are courtesy of Kyle Richardson.

Some photos of the Tornado warned storm earlier today (July 3), in Allen and Martin, SD area. #sdwx pic.twitter.com/MNNR8w5Sqc
— Tayler Fuchs (@tayler_fuchs54) July 4, 2019

Yikes.

Found near the Doty fire station on Nemo road earlier this afternoon! Thanks so much Eric O’Conner!

Still confirming approximate time @NWSRapidCity pic.twitter.com/RX9bxXrjOO
— Brant Beckman â›ˆ (@BrantBeckmanwx) July 4, 2019

Spotters reported 4 funnel clouds in Allen/Swett area. 2 touching down briefly. Strong Straight Line Winds are believed to have caused all the damage. Up to quarter size hail damaged crops. Brief heavy rain reported. pic.twitter.com/FkxnjwE55b
— Martin Vol Fire Dept (@martin_vol) July 4, 2019

Radar


Radar reflectivity (left) and velocity (right) near the time of the first tornado west of Allen, SD (valid 4:05 pm MDT, July 3, 2019)	Radar reflectivity (left) and velocity (right) when the tornado had started southwest of Dewey, SD (valid 4:28 pm MDT, July 3, 2019)

Storm Reports

Here are the preliminary severe thunderstorm storm reports for July 3, 2019.

Preliminary storm reports for July 3, 2019 (green H's represent hail; blue W's represent wind gusts; the red T's represent tornado reports)

The storm reports listed below are in descending order and may not
necessarily be the final storm reports.

Hail reports listed by size (inches)

 SIZE    LOCATION                 ST  COUNTY           TIME
 ------  -----------------------  --  --------------   -------
  2.00   10 WNW PINE TREE JUNCTI  WY  CAMPBELL         0820 PM
  1.75   10 W ROCKYFORD           SD  OGLALA LAKOTA    0738 PM
  1.75   11 NNE EDGEMONT          SD  FALL RIVER       0706 PM
  1.75   9 SSW JEWEL CAVE         SD  CUSTER           0531 PM
  1.75   BOX ELDER                SD  PENNINGTON       0530 PM
  1.75   7 SSW BATESLAND          SD  OGLALA LAKOTA    0514 PM
  1.75   5 E PORCUPINE            SD  OGLALA LAKOTA    0424 PM
  1.75   8 S KYLE                 SD  OGLALA LAKOTA    0415 PM
                 SHEET METAL TORN OFF ROOF, 10-15 LARGE LIMBS
                 BROKEN OFF COTTONWOOD TREES.
  1.75   7 W ROCKYFORD            SD  OGLALA LAKOTA    0300 PM
  1.50   PRINGLE                  SD  CUSTER           0600 PM
  1.25   2 E SUMMERSET            SD  MEADE            0530 PM
                 HAIL FELL 10 MINUTES FROM 530-540 PM. LARGEST
                 SIZE WAS HALF DOLLARS, BUT MOST WERE MARBLE
                 SIZED.
  1.25   7 W ROCKYFORD            SD  OGLALA LAKOTA    0320 PM
  1.00   7 ENE ROCHELLE           WY  WESTON           1015 PM
  1.00   5 SW HOT SPRINGS         SD  FALL RIVER       0715 PM
  1.00   9 ESE DEWEY              SD  CUSTER           0648 PM
  1.00   DEWEY                    SD  CUSTER           0624 PM
  1.00   DEWEY                    SD  CUSTER           0620 PM
  1.00   6 NNW BUFFALO GAP        SD  CUSTER           0615 PM
  1.00   4 NNE MILLBORO           SD  TRIPP            0550 PM
  1.00   2 E SUMMERSET            SD  MEADE            0534 PM
  1.00   SUMMERSET                SD  MEADE            0525 PM
  1.00   ELLSWORTH AFB            SD  MEADE            0518 PM
  1.00   1 WNW ELLSWORTH AFB      SD  MEADE            0515 PM
  1.00   3 NW DWTN RAPID CITY     SD  PENNINGTON       0455 PM
  1.00   4 NE JOHNSON SIDING      SD  PENNINGTON       0440 PM
  1.00   2 NNE JOHNSON SIDING     SD  PENNINGTON       0420 PM
  1.00   3 NNE WEWELA             SD  TRIPP            0405 PM
  1.00   5 ESE SHARPS CORNER      SD  OGLALA LAKOTA    0346 PM
  1.00   CLEARFIELD               SD  TRIPP            0345 PM
  1.00   5 WSW KYLE               SD  OGLALA LAKOTA    0339 PM

Tstm wind reports listed by speed (mph)

 SPEED   LOCATION                 ST  COUNTY           TIME
 ------  -----------------------  --  --------------   -------
 78.00   5 NE PORCUPINE           SD  OGLALA LAKOTA    0441 PM
 70.00   3 WSW SWETT              SD  BENNETT          0438 PM
 65.00   1 NW SAINT FRANCIS       SD  TODD             0712 PM
                 ESTIMATED BETWEEN 60 AND 70 MPH WINDS
 64.00   1 NE MIDLAND             SD  HAAKON           0825 PM
 64.00   3 E PHILIP               SD  HAAKON           0726 PM
 62.00   1 NE WINNER              SD  TRIPP            0859 PM
 60.00   3 NNW WITTEN             SD  TRIPP            0915 PM
 60.00   BELVIDERE                SD  JACKSON          0836 PM
 60.00   2 NE KADOKA              SD  JACKSON          0757 PM
 60.00   8 ESE SAINT FRANCIS      SD  TODD             0715 PM
                 1 INCH DIAMETER BRANCHES DOWN
 60.00   13 NNW WITTEN            SD  TRIPP            0630 PM
 60.00   VETAL                    SD  BENNETT          0628 PM
 53.00   1 NE WINNER              SD  TRIPP            0853 PM
 50.00   7 ENE ROCHELLE           WY  WESTON           0915 PM
 50.00   MIDLAND                  SD  HAAKON           0830 PM
 50.00   6 W PARMELEE             SD  TODD             0728 PM
 50.00   6 W PARMELEE             SD  TODD             0648 PM
 50.00   5 E PORCUPINE            SD  OGLALA LAKOTA    0425 PM

--------------------------------------------------------------

Straight-line wind damage near Allen, SD (image obtained from KOTA TV)

Environment

Click here for a satellite animation of the event.

The environment was unstable with a lot of energy available for severe thunderstorms (left image). The vertical wind shear (middle image) was strong enough for organized severe storms over most of the area. Finally, the significant tornado parameter (used to assess the potential for EF2 or greater tornadoes) was supportive of tornadoes in the area where they occurred.


MLCAPE (a measure of buoyancy) valid at 4 pm MDT, July 3, 2019	0-6km wind shear (indicative of storm severity) valid at 4 pm MDT, July 3, 2019	Significant tornado parameter (suggestive of EF2 or greater tornadoes) valid at 4 pm MDT, July 3, 2019

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