April 1, 2011 Spring and Summer Streamflow Forecasts
Missouri River Basin Streamflow Forecast Missouri River Basin Mountain Snowpack
Upper Missouri Basin
THE HIGH ELEVATION SNOW PACK IN THE UPPER MISSOURI BASIN AS OF
APRIL 1 WAS ABOVE AVERAGE. THE SNOW PACK ABOVE TOSTON,
MONTANA WAS 114 PERCENT OF AVERAGE. THE SNOW PACK BETWEEN TOSTON
AND FORT PECK, MONTANA WAS 120 PERCENT. THE SNOW PACK IN THE
ST MARY AND MILK RIVER BASINS WAS 127 PERCENT.
MARCH PRECIPITATION ACROSS THE UPPER MISSOURI BASIN WAS AVERAGE TO
ABOVE AVERAGE. BASIN PRECIPITATION SUMMARIES FOR THE MISSOURI
BASIN INCLUDE: MILK ST. MARY, 91 PERCENT; MILK CANADA, 115 PERCENT;
LOWER MILK, 150 PERCENT; ABOVE TOSTON, 102 PERCENT; TOSTON TO
FT. PECK, 97 PERCENT.
March 2011 Upper Missouri Mean Precip Oct-Mar WY2011 Upper Missouri Mean Precip
STREAM FLOW IN THE UPPER MISSOURI BASIN IS FORECAST TO BE NEAR TO
ABOVE AVERAGE DURING THE UPCOMING SPRING AND SUMMER. THE ST.
MARY RIVER IS FORECAST TO HAVE 114 PERCENT OF AVERAGE APRIL-SEPTEMBER
FLOWS. RUNOFF IS EXPECTED TO RANGE AROUND 115 PERCENT OF AVERAGE
FOR THE MISSOURI BASIN ABOVE FORT PECK, MONTANA. FORECASTS FOR THE
MILK RIVER BASIN CALL FOR AROUND 130 TO 160 PERCENT OF AVERAGE SPRING
SUMMER RUNOFF.
Upper Missouri April 1, 2011 Spring and Summer Streamflow Forecasts
OF THE FOUR MAJOR IRRIGATION RESERVOIRS IN MONTANA: LIMA RESERVOIR
HAD 129 PERCENT AVERAGE STORAGE, CLARK CANYON WAS HOLDING 106 PERCENT OF
AVERAGE WATER, GIBSON RESERVOIR HAD 30 PERCENT OF AVERAGE STORED
WATER, AND FRESNO RESERVOIR HAD 114 PERCENT OF AVERAGE STORED WATER.
THE MAJOR HYDROELECTRIC RESERVOIRS IN MONTANA (CANYON FERRY AND
FORT PECK) HAD MONTHEND STORAGE IN THE AVERAGE RANGE; 95 AND 107 PERCENT
OF AVERAGE WATER, RESPECTIVELY.
Yellowstone Basin
THE HIGH ELEVATION SNOW PACK IN THE YELLOWSTONE BASIN WAS ABOVE
AVERAGE ON APRIL 1. THE SNOW PACK IN THE UPPER YELLOWSTONE BASIN
WAS 119 PERCENT OF AVERAGE. THE SNOW PACKS IN THE WIND, BIGHORN,
AND SHOSHONE BASINS WERE 104, 113, AND 111 PERCENT OF AVERAGE,
RESPECTIVELY. THE SNOW PACKS IN THE TONGUE AND POWDER BASINS WERE
108 AND 117 PERCENT OF AVERAGE, RESPECTIVELY.
PRECIPITATION DURING MARCH RANGED FROM BELOW AVERAGE TO MUCH ABOVE
AVERAGE. THE UPPER YELLOWSTONE RIVER BASIN RECEIVED 145 PERCENT OF
AVERAGE PRECIPITATION WHILE THE LOWER YELLOWSTONE BASIN REPORTED 105
PERCENT OF AVERAGE. THE BIGHORN BASIN RECEIVED 103 PERCENT OF
AVERAGE PRECIPITATION WHILE THE WIND RIVER BASIN RECEIVED 64 PERCENT
OF AVERAGE. THE LITTLE BIGHORN - UPPER TONGUE BASIN RECEIVED 105
PERCENT OF AVERAGE AND THE POWDER RIVER HAD 175 PERCENT OF AVERAGE
PRECIPITATION.
March 2011 Yellowstone Mean Precip Oct-Mar WY2011 Yellowstone Mean Precip
STREAM FLOW IN THE YELLOWSTONE BASIN IS FORECAST TO BE MOSTLY ABOVE
AVERAGE DURING THE UPCOMING SPRING AND SUMMER. RUNOFF AT
BILLINGS, MONTANA IS EXPECTED TO BE 124 PERCENT OF AVERAGE, WITH
A PROBABLE RANGE BETWEEN 97 AND 150 PERCENT OF AVERAGE. STREAM
FLOW FOR THE WIND-BIGHORN BASIN ABOVE ST. XAVIER, MONTANA IS
FORECAST TO BE 107 PERCENT OF AVERAGE WITH A PROBABLE RANGE
OF 67 TO 147 PERCENT OF AVERAGE. FLOW IN THE TONGUE BASIN IS
EXPECTED TO BE 106 PERCENT OF AVERAGE WITH A REASONABLY LIKELY RANGE
OF 64 TO 148 PERCENT OF AVERAGE FLOW. FLOWS IN THE POWDER RIVER ARE
EXPECTED TO BE ABOUT 108 PERCENT OF AVERAGE WITH A REASONABLY LIKELY
RANGE OF 51 TO 165 PERCENT.
END-OF-MARCH RESERVOIR STORAGE IN WYOMING WAS 100 PERCENT OF
AVERAGE IN BOYSEN RESERVOIR AND 111 PERCENT OF AVERAGE IN BUFFALO
BILL RESERVOIR. MONTHEND STORAGE WAS 107 PERCENT OF AVERAGE IN
BIGHORN RESERVOIR ON THE WYOMING/MONTANA BORDER.
Yellowstone April 1, 2011 Spring and Summer Streamflow Forecasts
Platte Basin
THE HIGH ELEVATION SNOW PACK IN THE UPPER NORTH PLATTE BASIN WAS
134 PERCENT OF AVERAGE ON APRIL 1. THE SNOW PACK IN THE NORTH
PLATTE BASIN BELOW SEMINOE RESERVOIR WAS 116 PERCENT OF AVERAGE.
THE SNOW PACK IN THE SOUTH PLATTE BASIN WAS 123 PERCENT OF AVERAGE.
MARCH PRECIPITATION ACROSS THE PLATTE BASIN WAS MOSTLY BELOW AVERAGE.
PRECIPITATION DURING MARCH IN THE NORTH PLATTE BASIN ABOVE SEMINOE
RESERVOIR WAS 114 PERCENT OF AVERAGE. IN THE NORTH PLATTE BASIN BETWEEN
SEMINOE RESERVOIR AND GUERNSY RESERVOIR PRECIPITATION WAS 75 PERCENT
OF AVERAGE. THE NORTH PLATTE BASIN BELOW GUERNSY RESERVOIR HAD 75
PERCENT OF AVERAGE PRECIPITATION. THE HIGH ELEVATIONS OF THE SOUTH
PLATTE BASIN HAD 47 PERCENT OF AVERAGE PRECIPITATION WHEREAS THE PLAINS
HAD 40 PERCENT OF AVERAGE FEBRUARY PRECIPITATION.
March 2011 Platte Mean Precip Oct-Mar WY2011 Platte Mean Precip
STREAM FLOW IN THE PLATTE BASIN IS FORECAST TO RANGE FROM AVERAGE
TO ABOVE AVERAGE DURING THE UPCOMING SPRING AND SUMMER.
RUNOFF FOR STREAMS ABOVE SEMINOE RESERVOIR ARE EXPECTED TO BE FROM
130 TO 170 PERCENT OF AVERAGE. STREAM FLOWS FOR THE NORTH PLATTE
BELOW SEMINOE RESERVOIR ARE FORECAST TO BE 90 TO 160 PERCENT OF
AVERAGE. STREAMS IN THE SOUTH PLATTE BASIN ABOVE SOUTH PLATTE,
COLORADO CAN EXPECT 40 TO 115 PERCENT OF AVERAGE FLOW. FOR THE
REMAINDER OF THE SOUTH PLATTE BASIN FLOWS ARE EXPECTED VARY FROM
50 TO 130 PERCENT OF AVERAGE.
STORED WATER IN THE SOUTH PLATTE BASIN WAS 99 PERCENT OF AVERAGE
ON APRIL 1. STORED WATER IN THE NORTH PLATTE BASIN WAS 120
PERCENT OF AVERAGE.
North Platte Streamflow Fcst South Platte Streamflow Fcst
