Dangerously hot conditions are occurring today in southeast Oklahoma, the ArkLaTex, lower Mississippi Valley, and Puerto Rico. Hot temperatures surround this area throughout the southern U.S. Excessive Heat Warnings and Heat Advisories in effect. Excessive rainfall may lead to flash flooding today over parts of northern Alabama into eastern Tennessee and the Cascades. Read More >
Overview
During the afternoon and evening of July 18, 2018, scattered strong to severe thunderstorms developed across western South Dakota. The most intense storm produced a brief tornado and significant straight-line wind damage over northeastern Tripp County, north of Hamill. Based on a storm damage survey, the highest winds of the tornado were estimated to be 90 to 100 mph, which gives it a rating of EF-1. In addition, straight-line winds snapped trees and power poles, with estimated wind speeds up to 115 mph. This storm is pictured to the left. Photo courtesy of Laura Welker from Hamill.
Farther west, a severe thunderstorm produced hail up to two inches in diameter and wind gusts to 70 mph across portions of Pennington, Custer, and Oglala Lakota Counties. The storm also produced locally heavy rainfall, which led to water over roadways across portions of Pennington County.
Tornadoes:
Tornado - North of Hamill, SD
Track Map ![]() ![]() Downloadable KMZ File |
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 |
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Photos & Video:
Tripp County Tornado and Straight-Line Wind Damage
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Irrigation Pivot Blown Over |
Irrigation Pivot Blown Over |
Irrigation Pivot Moved |
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Power Pole Damage |
Shed Destroyed |
Outbuilding Damaged and Moved |
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Tree Damage |
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Storm Approaching |
Storm Video recorded from Rapid City Weather Forecast Office
Hail and Heavy Rain Photos
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Box Elder |
Box Elder |
Box Elder |
Box Elder |
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Box Elder |
South of Box Elder |
South of Box Elder |
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Box Elder |
South of Box Elder |
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South of Box Elder |
North of I-90 |
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Water on Radar Hill Road |
Hail Damage to Vehicle, south of Box Elder |
Radar:
Overview
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Radar from 3 PM through 9 PM MDT on 7/18/2018 |
Tripp County Tornado
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Radar Reflectivity (storm intensity) | Radar Storm-Relative Velocity (wind) |
Storm Reports
Map of preliminary storm reports from July 18, 2018. Red T's, blue W's, and green H's show tornado, wind, and hail reports, respectively. |
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0238 PM TSTM WND GST ELLSWORTH AFB 44.15N 103.10W
07/18/2018 M51 MPH MEADE SD OTHER FEDERAL
0248 PM TSTM WND GST 1 E DOWNTOWN RAPID CITY 44.07N 103.21W
07/18/2018 M60 MPH PENNINGTON SD OFFICIAL NWS OBS
0248 PM HAIL BOX ELDER 44.12N 103.07W
07/18/2018 M2.00 INCH PENNINGTON SD SOCIAL MEDIA
0251 PM HAIL BOX ELDER 44.12N 103.07W
07/18/2018 M1.75 INCH PENNINGTON SD SOCIAL MEDIA
0252 PM HAIL 5 E DOWNTOWN RAPID CITY 44.08N 103.13W
07/18/2018 E1.00 INCH PENNINGTON SD NWS EMPLOYEE
0252 PM TSTM WND GST 5 E DOWNTOWN RAPID CITY 44.08N 103.13W
07/18/2018 E60 MPH PENNINGTON SD NWS EMPLOYEE
0253 PM TSTM WND GST RAPID CITY AIRPORT 44.05N 103.06W
07/18/2018 M70 MPH PENNINGTON SD ASOS
0313 PM HAIL 2 SE FARMINGDALE 43.95N 102.86W
07/18/2018 M1.25 INCH PENNINGTON SD TRAINED SPOTTER
0325 PM HAIL 4 SE FOLSOM 43.80N 102.81W
07/18/2018 M1.00 INCH CUSTER SD TRAINED SPOTTER
0325 PM TSTM WND DMG 4 SE FOLSOM 43.80N 102.81W
07/18/2018 CUSTER SD TRAINED SPOTTER
LARGE TREE BRANCHES BROKEN.
0358 PM TSTM WND GST 1 NNE ROCKYFORD 43.51N 102.50W
07/18/2018 E60 MPH OGLALA LAKOTA SD TRAINED SPOTTER
0410 PM HAIL 19 S OKREEK 43.10N 100.34W
07/18/2018 M1.00 INCH TODD SD PUBLIC
0630 PM TSTM WND DMG 5 N HAMILL 43.66N 99.67W
07/18/2018 TRIPP SD TRAINED SPOTTER
A SHED WAS LEVELED, MANY WINDOWS BROKEN, CEDAR TREES
UPROOTED, 2 VERY LARGE PINE TREES BROKEN OFF ONE 6 FEET
OFF THE GROUND THE OTHER ABOUT 12 FEET OFF THE GROUND.
0655 PM TSTM WND GST 2 W HAMILL 43.59N 99.71W
07/18/2018 M52 MPH TRIPP SD MESONET
HAIL REPORTS LISTED BY SIZE (INCHES)
SIZE LOCATION ST COUNTY TIME
------ ----------------------- -- -------------- -------
2.00 BOX ELDER SD PENNINGTON 0248 PM
1.75 BOX ELDER SD PENNINGTON 0251 PM
1.25 2 SE FARMINGDALE SD PENNINGTON 0313 PM
1.00 19 S OKREEK SD TODD 0410 PM
1.00 4 SE FOLSOM SD CUSTER 0325 PM
1.00 5 E DOWNTOWN RAPID CITY SD PENNINGTON 0252 PM
TSTM WIND REPORTS LISTED BY SPEED (MPH)
SPEED LOCATION ST COUNTY TIME
------ ----------------------- -- -------------- -------
70.00 RAPID CITY AIRPORT SD PENNINGTON 0253 PM
60.00 1 NNE ROCKYFORD SD OGLALA LAKOTA 0358 PM
60.00 5 E DOWNTOWN RAPID CITY SD PENNINGTON 0252 PM
60.00 1 E DOWNTOWN RAPID CITY SD PENNINGTON 0248 PM
56.00 3 ESE PINE RIDGE SD OGLALA LAKOTA 1034 PM
52.00 2 W HAMILL SD TRIPP 0655 PM
51.00 ELLSWORTH AFB SD MEADE 0238 PM
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