Ice break-up and runoff from melting snow caused minor to moderate flooding across northwestern South Dakota.
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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.
Ice break-up and runoff from melting snow caused minor to moderate flooding across northwestern South Dakota.
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 Mar 15, 7:24 PM MST, 4 hours 36 minutes earlier.
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 824 PM MDT TUE MAR 15 2011 .DISCUSSION...CURRENT SURFACE MAP SHOWS A TROUGH IN THE LEE OF THE ROCKIES STRETCHING FROM COLORADO TO THE CANADIAN BORDER...SETTING UP SOUTHEASTERLY WINDS OVER MUCH OF THE FORECAST AREA. ALOFT...WV LOOP SHOWS A STREAM OF MOISTURE MOVING OFF THE PACIFIC INTO THE INLAND NORTHWEST...WHILE DRIER ASSOCIATED WITH A RIDGE IS EVIDENT OVER THE NORTHERN PLAINS. HAVE MADE SOME MINOR UPDATES TO TEMPS AND WINDS...OTHERWISE EXISTING FORECAST IN ON TRACK. CONTINUING TO MONITOR AREA STREAMS AND RIVERS FOR FLOODING CONCERNS. && .PREV DISCUSSION... /ISSUED 250 PM MDT TUE MAR 15 2011/ DISCUSSION...CURRENT SURFACE MAP SHOWS WEAK TROF ACROSS MONTANA INTO EASTERN WYOMING. UPPER LEVEL RIDGE ACROSS THE AREA WITH A FEW MID/HIGH CLOUDS. FOR TONIGHT...PRESSURE FALLS ACROSS THE WESTERN DAKOTAS WILL ALLOW FOR GUSTY SOUTHWEST WINDS TO DEVELOP ACROSS NORTHEAST WYOMING AND DOWN SLOPE AREA OF NORTHERN/EASTERN FOOTHILLS. 18Z NAM SHOWING 4MB PRESSURE GRADIENT ACROSS BLACK HILLS WITH 30-40KT BOUNDARY LAYER WINDS. STRONGEST WINDS ARE ABOVE INVERSION. MAY BRIEFLY REACH ADVISORY CRITERIA IN THE FOOTHILLS. COULD ALSO SEE SOME GUSTY WINDS DOWNSTREAM OF THE PINE RIDGE. LOW LEVEL THERMAL RIDGE ACROSS THE AREA WEDNESDAY MORNING. COLD FRONT TO SLIDE INTO WESTERN SOUTH DAKOTA DURING THE AFTERNOON. SUFFICIENT MIXING AHEAD SHOULD ALLOW A FEW LOCATIONS TO REACH THE LOWER 70S. PRECIPITATION LIKELY WEDNESDAY NIGHT AS BAROCLINIC ZONE PROVIDES FOCUS OVER THE AREA. Q-G FORCING WILL ONLY BE MODEST BUT LAPSE RATES OF 6-7 C/KM WILL HELP INCREASE VERTICAL MOTION. SHOWERS WILL LINGER ON THURSDAY AS AN UPPER JET STREAK REMAINS OVER THE AREA. EXTENDED...WEAK RIDGING ON FRIDAY AND SATURDAY WILL BRING DRY AND MILD WEATHER TO MOST LOCATIONS...THOUGH A FEW SNOW SHOWERS MAY LINGER FRIDAY MORNING OVER THE NORTHERN BLACK HILLS. BY SATURDAY NIGHT...UPPER FLOW BECOMES MORE SOUTHWESTERLY AS A TROF DIGS INTO THE WESTERN CONUS. A LOW PRESSURE SYSTEM WILL EJECT FROM THE ROCKIES INTO THE NORTHERN PLAINS SATURDAY EVENING INTO SUNDAY. MODELS ARE CONTINUING TO SHIFT THIS SYSTEM TO THE NORTH...WITH A MAJORITY OF THE PRECIP REMAINING NORTH AND EAST OF THE AREA. WITH THAT SAID...SOME RAIN AND SNOW SHOWERS MAY DEVELOP SATURDAY EVENING WITH THE POSSIBILITY OF A THUNDERSTORM OVER THE SOUTHERN CWFA WHERE SOME WEAK INSTABILITY IS EXPECTED. TEMPERATURES WILL REMAIN GENERALLY WARM SUNDAY BEFORE COOLER AIR WRAPS BEHIND THE LOW FOR MONDAY. AVIATION...VFR CONDITIONS WILL PERSIST THROUGH THE FORECAST PERIOD. SOME LOW LEVEL WIND SHEAR IS EXPECTED FOR KRAP AFTER MIDNIGHT INTO EARLY TUESDAY MORNING. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && VAN CLEAVE
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RAPID CITY SD 835 PM MDT TUE MAR 15 2011 SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058- 071-161300- 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- 835 PM MDT (935 PM CDT) TUE MAR 15 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN SOUTH DAKOTA AND NORTHEASTERN WYOMING. .DAY ONE...TODAY AND TONIGHT WARM WEATHER WILL CONTINUE TO RESULT IN RIVER FLOODING FROM ICE JAMS AND SNOWMELT ACROSS PORTIONS OF WESTERN AND SOUTH CENTRAL SOUTH DAKOTA TODAY AND TONIGHT...MAINLY ALONG THE WHITE...CHEYENNE...AND BAD RIVERS. SEE THE LATEST FLOOD WARNING PRODUCTS FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY MILD WEATHER WILL CONTINUE THROUGH THE WEEK...LEADING TO SIGNIFICANT SNOWMELT AND LIKELY FLOODING OVER PORTIONS OF NORTHEASTERN WYOMING AND NORTHWESTERN SOUTH DAKOTA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
1036 PM MDT TUE MAR 15 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1000 PM FLOOD 10 N WHITE RIVER 43.71N 100.74W
03/15/2011 MELLETTE SD DEPT OF HIGHWAYS
THE WHITE RIVER HAS RISEN AND IS FLOWING OVER PARTS OF
HIGHWAY 83 AT THE BRIDGE SOUTH OF MURDO. STATE DOT HAS
CLOSED THE BRIDGE.
&&
JOHNSONThe national radar mosaic for the moment the first event began.
2 flood. Local standard time, as filed.
Minor flooding occurred along the Little Missouri River, forcing the closure of county roads near the river. The river gage at Camp Crook crested at 15.3 feet, or 3.3 feet above flood stage.
Moderate flooding occurred along the Moreau River, forcing the closure of county roads near the river. The river gage along SD Highway 73 northwest of Faith crested at 19.95 feet, or 3.95 feet above flood stage.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Dakota in 2011Every state in 2011This day in weather historyWarnings in South Dakota, March 2011
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: 284313, 284363.