After a snow storm on May 9-10 left a liquid equivalent of one to three inches of precipitation over southwestern South Dakota and northwestern Nebraska, additional rain combined with the melting snow to cause flooding in the White River, Cheyenne River, and Bad River basins. Record flooding was recorded on the White River in Shannon County.
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.
After a snow storm on May 9-10 left a liquid equivalent of one to three inches of precipitation over southwestern South Dakota and northwestern Nebraska, additional rain combined with the melting snow to cause flooding in the White River, Cheyenne River, and Bad River basins. Record flooding was recorded on the White River in Shannon 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 May 13, 7:34 PM MST, 26 minutes earlier.
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 834 PM MDT WED MAY 13 2015 .UPDATE... ISSUED AT 833 PM MDT WED MAY 13 2015 FORECAST REMAINS ON TRACK. MADE SOME MINOR ADJUSTMENTS TO POPS AND REDUCED THUNDERSTORM COVERAGE. && .SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT ISSUED AT 147 PM MDT WED MAY 13 2015 19Z SURFACE ANALYSIS HAD LOW NEAR KPHP WITH FRONTAL BOUNDARY INTO EASTERN CO AND WARM FRONT INTO SOUTHERN MN. WATER VAPOUR LOOP HAD NICE LOOKING SHORTWAVE HEADING OVER THE OK PANHANDLE WITH 90KT JET STREAK AHEAD OF IT. 80KT WEST-EAST ORIENTED JET STREAK NOTED OVER THE DAKOTAS. SHORTWAVE WILL PUSH NORTH/NORTHEAST TONIGHT WITH JET STREAKS PROVIDING UPPER LEVEL DIVERGENCE/LIFT WITH SHORTWAVE. 0.5-1KJ/KG MLCAPE FORECAST ALONG FRONTAL BOUNDARY...BUT LACK OF STRONG SOLAR INSOLATION THIS AFTERNOON MAY INHIBIT THE HIGHER VALUES. COMBINATION OF THESE FEATURES WILL ALLOW SHRA/TSRA TO INCREASE IN COVERAGE THIS AFTERNOON/EVENING...AND THEN MOVE NORTH/NORTHEAST OVERNIGHT. ISOLATED SEVERE STORMS NOT OUT OF THE QUESTION GIVEN 0-6KM BULK SHEAR NORTHWEST OF FRONTAL BOUNDARIES...BUT SHEAR DECREASES TONIGHT AS WIND FIELDS LESSEN DIRECTLY UNDER 850-700MB CIRCULATION MOVING THROUGH CWA. TEMPERATURES WILL BE NEAR GUIDANCE. THURSDAY...SURFACE BOUNDARY WILL REMAIN OVER CWA AS SHORTWAVE RIDGE/IMPLIED SUBSIDENCE CLEARS UP PRECIPITATION IN THE MORNING...ALTHOUGH EXTENSIVE CLOUDINESS LIKELY TO REMAIN GIVEN EXPECTED MOISTURE PROFILES. NEXT WAVE WILL APPROACH LATE IN THE DAY AND SPREAD POPS FROM SOUTHWEST TO NORTHEAST THURSDAY NIGHT. CONVECTIVE PARAMETERS LOOK MEAGER AT THIS TIME. TEMPERATURES WILL BE NEAR GUIDANCE. .LONG TERM...FRIDAY THROUGH WEDNESDAY ISSUED AT 147 PM MDT WED MAY 13 2015 GFS/GEM/ECMWF IN DECENT AGREEMENT FOR THIS WEEKEND. A LARGE UPPER LOW OVER THE SWRN CONUS 12Z FRIDAY WILL MOVE ACROSS THE INTERMOUNTAIN WEST AND INTO THE CNTRL PLAINS BY LATE SATURDAY. A LEAD SHORT-WAVE TROUGH WILL MOVE ACROSS THE BLKHLS FRIDAY AFTERNOON AND EVENING...BRINGING A VERY GOOD CHANCE OF SHRA/TSRA. SEVERE STORMS ARE EXPECTED FRIDAY ACROSS SRN SD GIVEN THE 40-50KT 0-6KM BULK SHEAR AND SBCAPE OF 1000-2000 J/KG. OTHERWISE...DECENT RAINFALL AMOUNTS OF 0.50-1.50 INCHES ARE POSSIBLE. A DRY SLOT THEN MOVES OVER MUCH OF THE AREA SATURDAY...ALLOWING FOR A RELATIVE MINIMUM IN PRECIP. THE BEST CHANCE WILL BE OVER THE NWRN CWA ON THE EDGE OF THE COMMA HEAD...AS WELL AS THE FAR ERN CWA NEAR THE SFC TROUGH WHERE SEVERE STORMS AGAIN WILL BE POSSIBLE. THE LOW THEN TRACKS OVER MINNESOTA BY LATE SUNDAY WITH SHOWERS LIKELY THROUGH THIS PERIOD. EVEN SOME SNOW IS POSSIBLE OVER THE HIGHER ELEVATIONS AS 850-MB TEMPS DROP TO NEAR 0C. MOSTLY DRY WEATHER IS THEN EXPECTED MONDAY THROUGH EARLY TUESDAY AS TRANSIENT UPPER-LEVEL RIDGING IS IN PLACE. AN ACTIVE PATTERN WILL REDEVELOP TUESDAY-WEDNESDAY AS THE GFS/ECMWF SHOW YET ANOTHER UPPER LOW CROSSING THE CNTRL/SRN ROCKIES. THE ECMWF IS NOTABLY COLDER THAN THE GFS...SO SNOW IN THE HIGHER ELEVATIONS AGAIN WILL BE POSSIBLE. && .AVIATION...FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING ISSUED AT 522 PM MDT WED MAY 13 2015 SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL OCCUR ACROSS NERN WY AND WRN SD THIS EVENING...WITH SHOWERS AND ISOLATED THUNDERSTORMS CONTINUING OVER WESTERN AND CENTRAL SOUTH DAKOTA AFTER 06Z. MVFR CIGS ARE EXPECTED WITH ANY SHOWERS AND STORMS. WIDESPREAD IFR/MVFR CIGS WITH AREAS OF FOG WILL DEVELOP LATE TNGT ACROSS PARTS OF NERN WY AND MUCH OF WRN SD. CONDITIONS WILL GRADUALLY IMPROVE AFT 15Z THURSDAY MORNING. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && UPDATE...10 SHORT TERM...HELGESON LONG TERM...BUNKERS AVIATION...10
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RAPID CITY SD 325 AM MDT WED MAY 13 2015 SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058- 071-141300- HARDING-PERKINS-BUTTE-NORTHERN MEADE CO PLAINS-ZIEBACH- NORTHERN BLACK HILLS-NORTHERN FOOT HILLS-RAPID CITY- SOUTHERN FOOT HILLS-CENTRAL BLACK HILLS-SOUTHERN BLACK HILLS- CUSTER CO PLAINS-PENNINGTON CO PLAINS-HAAKON-FALL RIVER-SHANNON- JACKSON-BENNETT-MELLETTE-TODD-TRIPP-STURGIS/PIEDMONT FOOT HILLS- SOUTHERN MEADE CO PLAINS-HERMOSA FOOT HILLS-NORTHERN CAMPBELL- SOUTHERN CAMPBELL-WESTERN CROOK-WYOMING BLACK HILLS-WESTON- NORTHEASTERN CROOK- 325 AM MDT WED MAY 13 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN SOUTH DAKOTA AND NORTHEASTERN WYOMING. .DAY ONE...TODAY AND TONIGHT SCATTERED TO ISOLATED THUNDERSTORMS CAN BE EXPECTED THIS AFTERNOON AND TONIGHT. ISOLATED SEVERE STORMS WILL BE POSSIBLE OVER NORTHEAST WYOMING AND THE BLACK HILLS...WITH HAIL BEING THE MAIN THREAT. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THERE ARE PERIODIC CHANCES FOR THUNDERSTORMS THROUGH THE END OF THE WEEK. A FEW THUNDERSTORMS MAY BE SEVERE FROM SOUTHWEST INTO SOUTH CENTRAL SOUTH DAKOTA FRIDAY...WITH LARGE HAIL...DAMAGING WINDS AND ISOLATED TORNADOES POSSIBLE. RUNOFF FROM MELTING SNOWS AND RECENT RAINS WILL CONTINUE TO CAUSE SOME FLOODING ALONG RIVERS ON THE SOUTH DAKOTA PLAINS. ADDITIONAL RAINFALL THIS WEEK MAY LEAD TO ADDITIONAL RIVER OR CREEK FLOODING TOWARD THE END OF THE WEEK...ESPECIALLY ALONG THE CHEYENNE...WHITE AND BAD RIVERS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY. && STAY TUNED TO NOAA WEATHER RADIO FOR FURTHER DETAILS OR UPDATES... OR CHECK OUR WEB SITE AT WEATHER.GOV/RAPIDCITY JC
The national radar mosaic for the moment the first event began.
9 flood. Local standard time, as filed.
Minor flooding of agricultural land occurred along the White River.
Record flooding occurred along the White River from the Nebraska state line to Badlands National Park. The White River was over 200 yards wide and at least two feet deep on BIA Highway 41 north of Oglala, where a vehicle was swept off the highway and the passengers had to be rescued. BIA Highway 32 near Slim Butte was washed out and a culvert on BIA Highway 27 washed out and the road was damaged north of Rockyford.
Minor flooding of agricultural land occurred along the Cheyenne River. At the Interstate 90 eastbound rest area near Wasta, water overflowed into the parking lot and surrounded the building.
Highway 44 and a campground near Interior were flooded due to runoff from more than two inches of rain and high water in the White River.
Minor flooding of agricultural land occurred along the Cheyenne River.
Minor flooding of agricultural land occurred along the South Fork of the Bad River and its tributaries.
Minor flooding of agricultural land occurred along the South Fork of the Bad River and its tributaries.
Minor flooding of agricultural land occurred along the Cheyenne River.
Minor flooding of agricultural land occurred along the White River.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Dakota in 2015Every state in 2015This day in weather historyWarnings in South Dakota, May 2015
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: 576859, 576887, 576894, 576900, 576897, 576890, 576893, 576895, 576899.