Late night severe thunderstorms moved across portions of northeast Wyoming, producing golf ball sized hail and strong wind gusts.
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.
Late night severe thunderstorms moved across portions of northeast Wyoming, producing golf ball sized hail and strong wind gusts.
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 Aug 7, 10:10 PM MST, 49 minutes earlier.
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 1110 PM MDT FRI AUG 7 2009 .DISCUSSION...SCT TSTMS CONT ACRS REGION AND ARE EXPECTED TO CONT THRU REST OF NIGHT. SEVERE ACTIVITY HAS QUIETED DOWN... THOUGH STILL A THREAT IN SOUTH CENTRAL SD FOR THE NEXT COUPLE OF HOURS. HAVE ALLOWED WATCH TO EXPIRE FOR ALL BUT TODD/TRIPP AND MELLETTE COUNTIES...WILL CONT WATCH UNTIL 100 AM MDT IN THOSE AREAS. PREVIOUS FORECAST DISCUSSION(300 PM MDT)...CURRENT SFC ANALYSIS SHOWS LOW PRESSURE ACROSS SOUTHWEST SD...SOUTH OF PHP...A BIT FURTHER SOUTH AND EAST THAN IT WAS EXPECTED TO BE. WARM FRONT LIES ACROSS SOUTHERN SD...WITH WEAK CDFNT BOUNDARY EXTENDING WESTWARD BACK TO ANOTHER AREA OF LOW PRESSURE AND MAIN CDFNT ACROSS CENTRAL AND WESTERN WY. APPEARS DEVELOPING DRYLINE OVER SOUTHEAST WY WILL NOT BE AS STRONG AND A BIT FURTHER SOUTH AND WEST. UPPER LEVEL ANALYSIS SHOWS LOW OVER ID...WITH SOUTHWEST FLOW ACROSS THE NORTHERN ROCKIES INTO THE NORTHERN HIGH PLAINS. STRONG JET ROUNDING THE LOW IS PUSHING NORTHEASTWARD ACROSS UT AND SOUTHWESTERN WY. SKIES ARE PARTLY CLOUDY TO MOSTLY SUNNY... WITH MOST CLOUDINESS ACROSS FAR NORTHWEST SD. KUDX RADAR IS CLR FOR THE MOMENT. TEMPS ARE MAINLY IN THE 70S AND 80S...COOLEST ACRS FAR NORTHWEST SD. SOME LOWER 90S NOTED ACROSS SOUTHWEST SD. WINDS ARE LIGHT N-NW ACROSS MOST OF THE AREA BEHIND THE LOW...SOUTHERLY SOUTH AND EAST OF IT. THUNDERSTORMS WILL LIKELY DEVELOP ACROSS THE AREA DURING THE LATE AFTERNOON AND EVENING HOURS...EARLIEST ACROSS THE HIGHER TERRAIN OF THE WY AND MT WHERE FORCING WILL BE THE GREATEST. BETTER THREAT THROUGH THE EVENING HOURS SHOULD GENERALLY BE NORTH OF INTERSTATE 90...ESPECIALLY ACROSS NORTHEAST WY INTO FAR NORTHWEST SD. INSTABILITY AND SHEAR WILL BE GREATEST IN THESE AREAS...WHERE SUPERCELLS COULD DEVELOP. CAPE VALUES OF OVER 2000 J/KG WILL BE IN PLACE LATER THIS AFTERNOON. LOW LEVEL SHEAR IS PROGGED TO BE QUITE STRONG AS WELL. ISOLATED TORNADO THREAT STILL EXISTS ACROSS THE NORTHERN AND EASTERN CWA...ESPECIALLY NORTHWESTERN SD. ACTIVITY THAT DEVELOPS FURTHER SOUTH ACROSS THE AREA SHOULD BE MORE ISOLATED IN NATURE...BUT COULD STILL SEE A FEW STRONG TO SEVERE STORMS AS WELL. LOOKS LIKE BETTER CHANCES FOR WIDESPREAD CONVECTION COULD COME OVERNIGHT INTO SATURDAY MORNING AS MAIN COLD FRONT CROSSES THE AREA. HAVE CHANCE TO LIKELY POPS ACROSS MUCH OF THE AREA DURING THIS TIME. FRONT WILL SLOWLY CROSS EASTERN PORTIONS OF THE CWA SATURDAY MORNING. MAIN THREAT FOR STRONGER STORMS SHOULD BE EAST OF THE CWA SATURDAY AFTERNOON. HOWEVER...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED AS UPPER TROF MOVES ACROSS THE NORTHERN ROCKIES. HIGHS WILL BE IN THE 70S AND 80S...WARMEST TOWARD SOUTH CENTRAL SD. UPPER TROF WILL WEAKEN AS IT CROSSES THE AREA SATURDAY NIGHT AND SUNDAY. WILL KEEP SOME LOW POPS IN THE FORECAST FOR MOST OF THE AREA. HIGHS ON SUNDAY WILL GENERALLY BE IN THE MID 70S TO MID 80S. EXTENDED...BROAD UPPER RIDGE DEVELOPS OVER THE NORTHERN PLAINS EARLY NEXT WEEK...WITH DRY WEATHER AND TEMPERATURES NEAR OR SLIGHTLY ABOVE AVERAGE. RIDGE BEGINS TO SHIFT EAST TOWARDS THE END OF THE WEEK WITH SOUTHWEST FLOW OVER THE NORTHERN PLAINS. MAY BE SOME ISOLATED THUNDERSTORM ACTIVITY...BUT WILL KEEP FORECAST DRY FOR NOW. && AVIATION...SCATTERED THUNDERSTORMS EXPECTED THROUGH TONIGHT WITH LCL MVFR/IFR CONDITIONS. MVFR/IFR CIGS EXPECTED TO SPREAD ACROSS NORTHEAST WYOMING AND NORTHWEST SOUTH DAKOTA TONIGHT BEHIND COLD FRONTAL PASSAGE. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RAPID CITY SD 307 AM MDT FRI AUG 7 2009 SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058- 071-081300- BENNETT-BUTTE-CENTRAL BLACK HILLS-CUSTER CO PLAINS-FALL RIVER-HAAKON- HARDING-HERMOSA FOOT HILLS-JACKSON-MELLETTE-NORTHEASTERN CROOK- NORTHERN BLACK HILLS-NORTHERN CAMPBELL-NORTHERN FOOT HILLS- NORTHERN MEADE CO PLAINS-PENNINGTON CO PLAINS-PERKINS-RAPID CITY- SHANNON-SOUTHERN BLACK HILLS-SOUTHERN CAMPBELL-SOUTHERN FOOT HILLS- SOUTHERN MEADE CO PLAINS-STURGIS/PIEDMONT FOOT HILLS-TODD-TRIPP- WESTERN CROOK-WESTON-WYOMING BLACK HILLS-ZIEBACH- 307 AM MDT (407 AM CDT) FRI AUG 7 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN SOUTH DAKOTA AND NORTHEASTERN WYOMING. .DAY ONE...TODAY AND TONIGHT THERE IS A CHANCE FOR THUNDERSTORMS TODAY AND TONIGHT. THUNDERSTORMS ARE FIRST EXPECTED ACROSS NORTHWEST AND CENTRAL SOUTH DAKOTA THIS AFTERNOON AND EVENING. THERE IS A SLIGHT RISK THAT SOME OF THESE THUNDERSTORMS WILL BECOME SEVERE. LARGE HAIL AND DAMAGING WIND GUSTS WILL BE THE MAIN THREATS. THERE IS ALSO THE POSSIBILITY THAT SOME OF THE STRONGER STORMS COULD PRODUCE A TORNADO... PARTICULARLY OVER NORTHWEST SOUTH DAKOTA. THE THUNDERSTORM COVERAGE WILL INCREASE TONIGHT AS A COLD FRONT DROPS SOUTH ACROSS THE FORECAST AREA. HOWEVER THE THREAT FOR SEVERE STORMS WILL DECREASE THROUGH THE LATE NIGHT HOURS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THERE IS A CHANCE FOR THUNDERSTORMS SATURDAY AND SUNDAY. WIDESPREAD SEVERE WEATHER IS NOT EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TODAY.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
839 PM MDT FRI AUG 07 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0835 PM HAIL 7 W MIDLAND 44.07N 101.29W
08/07/2009 E3.00 INCH HAAKON SD STORM CHASER
BROKEN WINDOWS.
&&
WETENKAMPPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
901 PM MDT FRI AUG 07 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0900 PM HAIL 5 E CACTUS FLAT 43.84N 101.80W
08/07/2009 E1.00 INCH JACKSON SD PUBLIC
&&
WETENKAMPPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
921 PM MDT FRI AUG 07 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0905 PM HAIL 10 NE BELVIDERE 43.94N 101.13W
08/07/2009 E1.75 INCH JACKSON SD PUBLIC
&&
WETENKAMPSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RAPID CITY SD 927 PM MDT FRI AUG 7 2009 SDZ027-029>031-041-042-074-080430- CUSTER CO PLAINS-FALL RIVER-HERMOSA FOOT HILLS-PENNINGTON CO PLAINS- SHANNON-SOUTHERN BLACK HILLS-SOUTHERN FOOT HILLS- INCLUDING THE CITIES OF...BUFFALO GAP...FAIRBURN... MAVERICK JUNCTION AND ORAL 927 PM MDT FRI AUG 7 2009 ...STRONG THUNDERSTORMS APPROACHING THE AREA... AT 926 PM MDT...DOPPLER RADAR INDICATED A LINE OF THUNDERSTORMS WITH PENNY SIZED HAIL AND FREQUENT CLOUD TO GROUND LIGHTNING. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM 8 MILES NORTH OF RED SHIRT TO 4 MILES SOUTHEAST OF WIND CAVE VISITORS CENTER...AND WERE MOVING EAST AT 25 MPH. LOCATIONS IMPACTED INCLUDE... MAVERICK JUNCTION... BUFFALO GAP... RED SHIRT... ORAL... ROCKYFORD... A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR THE AREA UNTIL 1100 PM MDT. TRIMARCHI
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RAPID CITY SD 949 PM MDT FRI AUG 7 2009 SDZ042-044-080445- BENNETT-SHANNON- INCLUDING THE CITIES OF...BATESLAND...PINE RIDGE... SWETT AND WOUNDED KNEE 949 PM MDT FRI AUG 7 2009 ...STRONG THUNDERSTORM APPROACHING THE AREA... AT 948 PM MDT...DOPPLER RADAR INDICATED A THUNDERSTORM WITH HEAVY RAIN...SMALL HAIL...AND FREQUENT CLOUD TO GROUND LIGHTNING. SOME AREAS MAY RECEIVE AS MUCH AS ONE INCH OF RAIN. THIS STORM WAS LOCATED 10 MILES SOUTHEAST OF WOUNDED KNEE...OR 14 MILES EAST OF PINE RIDGE...AND WAS MOVING EAST AT 25 MPH. LOCATIONS IMPACTED INCLUDE... BATESLAND... SWETT... A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR THE AREA UNTIL 1100 PM MDT. TRIMARCHI
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RAPID CITY SD 1131 PM MDT FRI AUG 7 2009 WYZ054-055-080630- NORTHERN CAMPBELL-SOUTHERN CAMPBELL- INCLUDING THE CITIES OF...DOWNTOWN GILLETTE AND ECHETA 1131 PM MDT FRI AUG 7 2009 ...STRONG THUNDERSTORM APPROACHING THE AREA... AT 1131 PM MDT...DOPPLER RADAR INDICATED A THUNDERSTORM WITH NICKEL SIZED HAIL...WIND GUSTS TO 50 MPH...AND FREQUENT CLOUD TO GROUND LIGHTNING. THIS STORM WAS LOCATED 15 MILES SOUTH OF ECHETA...OR 22 MILES WEST OF DOWNTOWN GILLETTE...AND WAS MOVING NORTHEAST AT 35 MPH. LOCATIONS IMPACTED INCLUDE... ECHETA... DOWNTOWN GILLETTE... THIS INCLUDES INTERSTATE 90 BETWEEN WYOMING MILE MARKERS 96 AND 131... JOHNSON
The Rapid City radar (KUDX), 221 km away, was scanning. The volume nearest the first event began at 06:01 UTC.
4 hail, 1 thunderstorm wind. Local standard time, as filed.
Hail damaged houses and automobiles in the Oriva Hills subdivision northwest of Gillette.
Wind gusts were estimated at 60 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2009Every state in 2009This day in weather historyWarnings in Wyoming, August 2009
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 2026-09-24. Each event’s entry at NCEI: 179373, 179374, 179375, 179376, 179377.