Missouri Basin River Forecast Center
Water Supply Statement
Issued in cooperation with the Natural
Resources Conservation Service
Issued:  May 10, 2006

RUNOFF FOR MOST STREAMS IN THE MISSOURI BASIN ARE FORECAST TO BE AVERAGE TO BELOW AVERAGE.  THE HIGH ELEVATION SNOW PACK IN THE MISSOURI BASIN IS GENERALLY BELOW AVERAGE FOR THIS TIME OF THE YEAR. PRECIPITATION IN THE MISSOURI BASIN WAS AVERAGE TO ABOVE IN MONTANA.  WYOMING HAD BELOW AVERAGE PRECIPITATION EXCEPT FOR THE POWDER RIVER BASIN WERE PRECIPITATION WAS ABOVE AVERAGE. NORTHEASTERN COLORADO REPORTED WELL BELOW AVERAGE PRECIPITATION.

Missouri River Basin Streamflow Forecast

Upper Missouri Basin

THE HIGH ELEVATION SNOW PACK IN THE UPPER MISSOURI BASIN AS OF MAY 1 WAS AVERAGE.  THE SNOW PACK ABOVE TOSTON, MONTANA WAS 105 PERCENT OF AVERAGE. THE SNOW PACK BETWEEN TOSTON AND FORT PECK, MONTANA WAS 90 PERCENT.  THE SNOW PACK IN THE ST MARY AND MILK RIVER BASINS WAS 85 PERCENT.

APRIL PRECIPITATION ABOVE TOSTON WAS ABOVE AVERAGE WITH 162 PERCENT OF NORMAL.  FROM TOSTON TO FT. PECK PRECIPITATION WAS ABOVE AVERAGE AT 187 PERCENT OF NORMAL.  THE ST. MARY AND MILK RIVER BASINS WERE ALSO ABOVE NORMAL WITH 103 AND 109 PERCENT OF NORMAL PRECIPITATION, RESPECTIVELY.



Apr 2006 Upper Missouri Mean Precip                     Oct-Apr WY2006 Upper Missouri Mean Precip

THE ST. MARY RIVER IS FORECAST TO HAVE 92 PERCENT OF AVERAGE MAY-SEPTEMBER FLOWS.  RUNOFF IS EXPECTED TO RANGE AROUND 105 PERCENT OF AVERAGE FOR THE MISSOURI BASIN ABOVE FORT PECK, MONTANA.  FORECASTS FOR THE MILK RIVER BASIN CALL FOR AROUND 80 PERCENT OF AVERAGE SPRING/SUMMER RUNOFF.

OF THE FOUR MAJOR IRRIGATION RESERVOIRS IN MONTANA:  LIMA RESERVOIR HAD 130 PERCENT AVERAGE STORAGE, CLARK CANYON WAS HOLDING 75 PERCENT OF AVERAGE WATER, GIBSON RESERVOIR HAD 88 PERCENT OF AVERAGE STORED WATER, AND FRESNO RESERVOIR HAD 102 PERCENT OF AVERAGE STORED WATER.  THE MAJOR HYDROELECTRIC RESERVOIRS IN MONTANA (CANYON FERRY AND FORT PECK) HAD MONTHEND STORAGE IN THE AVERAGE TO BELOW AVERAGE RANGE; 88 AND 62 PERCENT OF AVERAGE WATER, RESPECTIVELY.

AS INDICATED BY THE U.S. GEOLOGICAL SURVEY LONG TERM GAGING STATIONS, THE MARIAS RIVER NEAR SHELBY, MONTANA HAD AN ESTIMATED 109 PERCENT OF AVERAGE RUNOFF IN APRIL.  

Yellowstone Basin

THE HIGH ELEVATION SNOW PACK IN THE YELLOWSTONE BASIN WAS MOSTLY BELOW AVERAGE ON MAY 1.  THE SNOW PACK IN THE UPPER YELLOWSTONE BASIN WAS 88 PERCENT OF AVERAGE.  THE SNOW PACKS IN THE WIND, BIGHORN, AND SHOSHONE BASINS WERE 65, 66, AND 67 PERCENT OF AVERAGE, RESPECTIVELY.  THE SNOW PACKS IN THE TONGUE AND POWDER BASINS WERE 57 AND 60 PERCENT OF AVERAGE, RESPECTIVELY.

PRECIPITATION DURING THE MONTH OF APRIL WAS ABOUT 51 PERCENT OF AVERAGE IN THE WIND RIVER BASIN ABOVE BOYSEN RESERVOIR, 102 PERCENT OF AVERAGE IN THE UPPER YELLOWSTONE BASIN, 61 AND 79 PERCENT OF AVERAGE IN THE BIGHORN AND LITTLE BIGHORN BASINS, RESPECTIVELY, 134 PERCENT OF AVERAGE IN THE POWDER-TONGUE BASINS, AND 204 PERCENT OF AVERAGE IN THE LOWER YELLOWSTONE BASIN.



STREAM FLOW IN THE YELLOWSTONE BASIN IS FORECAST TO BE AVERAGE TO BELOW AVERAGE DURING THE UPCOMING SPRING AND SUMMER.  RUNOFF AT BILLINGS, MONTANA IS EXPECTED TO BE 97 PERCENT OF AVERAGE, WITH A PROBABLE RANGE BETWEEN 71 AND 124 PERCENT OF AVERAGE.  STREAM FLOW FOR THE WIND-BIGHORN BASIN ABOVE ST. XAVIER, MONTANA IS FORECAST TO BE 58 TO 67 PERCENT OF AVERAGE WITH A PROBABLE RANGE OF 26 TO 106 PERCENT OF AVERAGE FLOW IN SUB-BASINS.  FLOW IN THE TONGUE BASIN IS EXPECTED TO BE 64 TO 71 PERCENT OF AVERAGE WITH A REASONABLY LIKELY RANGE OF 25 TO 104 PERCENT OF AVERAGE FLOW.  FLOWS IN THE POWDER RIVER ARE EXPECTED TO BE ABOUT 59 TO 62 PERCENT OF AVERAGE WITH A REASONABLY LIKELY RANGE OF 35 TO 99 PERCENT.

MONTHEND STORAGE WAS AT 96 PERCENT OF AVERAGE AT BOYSEN RESERVOIR IN WYOMING, 134 PERCENT OF AVERAGE AT BUFFALO BILL RESERVOIR IN WYOMING, AND 97 PERCENT OF AVERAGE AT BIGHORN RESERVOIR ON THE WYOMING MONTANA BORDER.

RUNOFF DURING APRIL IN THE YELLOWSTONE RIVER WAS 115 PERCENT OF THE 1971 TO 2000 AVERAGE AT CORWIN SPRINGS, MONTANA AND 96 PERCENT OF THAT AVERAGE AT BILLINGS, MONTANA.   (HTTP:/MT.WATER.USGS.GOV/PUB/NWC.RELEASE.HTML)

Platte Basin

THE HIGH ELEVATION SNOW PACK IN THE UPPER NORTH PLATTE BASIN WAS 89 PERCENT OF AVERAGE ON MAY 1. THE SNOW PACK IN THE NORTH PLATTE BASIN BELOW SEMINOE RESERVOIR WAS 74 PERCENT OF AVEAGE. THE SNOW PACK IN THE SOUTH PLATTE BASIN WAS 84 PERCENT.

PRECIPITATION, DURING APRIL, IN NORTH PLATTE BASIN ABOVE SEMINOE RESERVOIR WAS 51 PERCENT AVERAGE.  PRECIPITATION IN THE NORTH PLATTE BASIN BETWEEN SEMINOE RESERVOIR AND GUERNSY RESERVOIR WAS 53 PERCENT OF AVERAGE.  THE NORTH PLATTE BASIN BELOW GUERNSY RESERVOIR HAD 44 PERCENT OF AVERAGE PRECIPITATION. THE HIGH ELEVATIONS OF THE SOUTH PLATTE BASIN HAD 37 PERCENT OF AVERAGE PRECIPITATION WHEREAS THE PLAINS HAD 40 PERCENT OF AVERAGE PRECIPITATION.


April 2006 Platte Mean Precip                                Oct-Apr WY2006 Platte Mean Precip


STREAM FLOW IN THE PLATTE BASIN ARE FORECAST TO BE BELOW AVERAGE DURING THE UPCOMING SPRING AND SUMMER. RUNOFF FOR STREAMS ABOVE SEMINOE RESERVOIR ARE EXPECTED TO BE BETWEEN 87 AND 06 PERCENT OF AVERAGE. STREAM FLOW FOR THE NORTH PLATTE BELOW SEMINOE RESERVOIR IS FORECAST TO BE BETWEEN 55 TO 87 PERCENT OF AVERAGE. THE SOUTH PLATTE BASIN ABOVE SOUTH PLATTE, COLORADO CAN EXPECT ABOUT 65 TO 80 PERCENT OF AVERAGE FLOW. FOR THE REMAINDER OF THE SOUTH PLATTE BASIN FLOWS ARE EXPECTED TO BE BETWEEN 65 AND 85 PERCENT OF AVERAGE.

STORED WATER IN THE NORTH PLATTE BASIN AS OF MAY 1 WAS 72 PERCENT OF AVERAGE. THE SOUTH PLATTE BASIN HAD 83 PERCENT OF AVERAGE STORED WATER.


          Precipitation Maps
 
 April 2006                Oct-Apr WY 2006

                          

April 2006 Precipitation Percent of 1971-2000 Average   Oct-Apr  WY2006 Precipitation as Percent of 1971-2000 Average


April 2006 Basin Mean Precipitation                     Oct-Apr WY2006 Basin Mean Precipitation

                               

April 2006 MBRFC Basin Mean Precipitation              Oct-Apr WY2006 MBRFC Basin Mean Precipitation

 

 

 


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