A long-lived supercell thunderstorm tracked from northeastern Wyoming, across the northern Black Hills, and to Bennett County before moving into Nebraska. The storm brought a swath of very large hail and strong wind gusts from south of Spearfish, to the Rapid City area, and across portions of the west central and southwestern South Dakota plains.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS UNR wrote it up.
A long-lived supercell thunderstorm tracked from northeastern Wyoming, across the northern Black Hills, and to Bennett County before moving into Nebraska. The storm brought a swath of very large hail and strong wind gusts from south of Spearfish, to the Rapid City area, and across portions of the west central and southwestern South Dakota plains. The storm produced two tornadoes; one across the northern Black Hills and the other over western Bennett County.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Rapid City, SD wrote its last area forecast discussion before the first event at Jul 10, 1:02 PM MST, 1 hour 33 minutes earlier.
Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 202 PM MDT Fri Jul 10 2020 .DISCUSSION...(This Evening Through Friday) Issued at 201 PM MDT Fri Jul 10 2020 The upper ridge over the region will continue to shift eastward as an upper trough approaches from the west. At the surface, an area of low pressure has developed over northeastern Wyoming, with an inverted trough extending northward into eastern Montana. Dry air, with RH values of 10 percent and gusty southerly winds are creating Red Flag conditions across northeast Wyoming. Radar imagery already has storms over northeastern Wyoming, and they will become severe sooner than later. Destabilization is occurring across northeastern Wyoming ahead of a quickly moving cold front in eastern Montana and a dryline in northeastern Wyoming. MUCAPE ranges from 1000 to 2500 J/kg and and strong deep sheer should support organized storms. Steep mid-level lapse rates will support large hail and possibly significant hail with storms. Also, any interactions with lingering boundaries may pose a tornadic threat; however, low-level shear is relatively weak. Saturday will be slightly cooler than today. With an upper ridge building to the west and a noticeably drier airmass in place at the surface, dry weather is expected for both Saturday and Sunday. More active weather will return for Sunday night through much of next week as an upper low slowly crosses the Canadian prairie provinces, producing a period of fast westerly flow over the northern plains. While models differ on the timing of the various disturbances in the flow, it appears there will be a chances for showers and thunderstorms on many days next week with temperatures near or slightly cooler than average. && .AVIATION...(For the 18Z TAFS Through 18Z Saturday) Issued At 201 PM MDT Fri Jul 10 2020 Severe storms will move continue to move from west to east this afternoon and evening from northeastern Wyoming into Western and South Central South Dakota. These storms will have strong and erratic winds as well as the possibility of large hail. VFR conditions expected outside of any storms. && .FIRE WEATHER... Issued at 201 PM MDT Fri Jul 10 2020 Critical fire weather conditions will continue through this evening. Relative humidity values are already around 10 percent near Wright. A cold front will push through northeastern Wyoming this afternoon. Ahead of the front, low RH values and gusty southerly winds are expected. Behind the front, winds will shift to the northwest and bring in higher dew points. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...Red Flag Warning until 9 PM MDT this evening for SDZ322. WY...Red Flag Warning until 9 PM MDT this evening for WYZ314>317. && DISCUSSION...MLS AVIATION...MLS FIRE WEATHER...MLS
Hazardous Weather Outlook National Weather Service Rapid City SD 503 AM MDT Fri Jul 10 2020 SDZ001-002-012>014-031-032-043-044-046-047-049-073-111300- Harding-Perkins-Butte-Northern Meade Co Plains-Ziebach- Pennington Co Plains-Haakon-Jackson-Bennett-Mellette-Todd-Tripp- Southern Meade Co Plains- 503 AM MDT Fri Jul 10 2020 /603 AM CDT Fri Jul 10 2020/ This Hazardous Weather Outlook is for portions of western South Dakota. .DAY ONE...Today and Tonight Severe thunderstorms are expected today. Large hail, damaging winds, and isolated tornadoes will be possible with these storms. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Additional thunderstorms will be possible from Sunday night through early next week. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today. && Stay tuned to NOAA weather radio for further updates...or check our web site at weather.gov/rapidcity SDZ024>030-041-042-072-074-WYZ054-056>058-071-111300- Northern Black Hills-Northern Foot Hills-Rapid City- Southern Foot Hills-Central Black Hills-Southern Black Hills- Custer Co Plains-Fall River-Oglala Lakota- Sturgis/Piedmont Foot Hills-Hermosa Foot Hills-Northern Campbell- Western Crook-Wyoming Black Hills-Weston-Northeastern Crook- 503 AM MDT Fri Jul 10 2020 This Hazardous Weather Outlook is for portions of northwestern South Dakota...southwestern South Dakota...the Black Hills of South Dakota...northeast Wyoming...and the Black Hills of Wyoming. .DAY ONE...Today and Tonight Thunderstorms are expected today, some of which could be severe. Large hail and damaging winds are possible from these storms. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Additional thunderstorms will be possible from Sunday night through early next week. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today. && Stay tuned to NOAA weather radio for further updates...or check our web site at weather.gov/rapidcity WYZ055-111300- Southern Campbell- 503 AM MDT Fri Jul 10 2020 This Hazardous Weather Outlook is for portions of northeast Wyoming. .DAY ONE...Today and Tonight No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Additional thunderstorms will be possible from Sunday night through much of next week. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today. && Stay tuned to NOAA weather radio for further updates...or check our web site at weather.gov/rapidcity
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</html>The Rapid City radar (KUDX), 100 km away, was scanning. The volume nearest the first event began at 21:32 UTC.
33 hail, 9 thunderstorm wind, 2 tornado. Local standard time, as filed.
The tornado tracked across forested terrain of the northern Black Hills for 15.5 miles. Many trees were snapped or uprooted along its path. Although the tornado itself did not cause property damage, trees were blown down onto houses and power lines.
Power lines and trees were downed over US Highway 14A between Cheyenne Crossing and Savoy.
The spotter estimated wind gusts around 60 mph.
Wind gusts were estimated at 60 mph.
Vehicle damage, including several broken windshields, was noted in the neighborhood.
Wind gusts were estimated at 80 mph.
Extensive roof and structural damage occurred at the Porcupine Dialysis Center, with one minor injury.
A 40 foot long trailer house was destroyed, outbuildings were damaged, and hay bales rolled a quarter of a mile.
An EF1 tornado tracked southeast across areas western Bennett County west and south of Swett. A mobile home was destroyed as it rolled 50 feet from its previous location. A few other homes on the edge of the tornado path were also damaged. Some large trees and branches were downed.
The tops of some trees were snapped off, large trees uprooted, and shingles were missing from structures.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Dakota in 2020Every state in 2020This day in weather historyThe tornado archive for South Dakota, 2020Warnings in South Dakota, July 2020
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 912403, 908950, 908952, 908954, 908955, 908957, 908964, 908966, 908959, 908960, 908961, 908967, 908980, 908962, 908969, 908971, 908973, 908974, 908975, 908977, 908982, 908985, 908990, 908994, 908996, 908998, 909000, 911598, 911599, 911600, 911601, 911602, 911603, 911604, 911605, 911606, 911607, 911608, 912432, 911609, and more.