May 1, 2012 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
MAY 1 WAS NEAR TO BELOW AVERAGE. THE SNOW PACK ABOVE TOSTON,
MONTANA WAS 75 PERCENT OF AVERAGE. THE SNOW PACK BETWEEN TOSTON
AND FORT PECK, MONTANA WAS 86 PERCENT. THE SNOW PACK IN THE
ST MARY AND MILK RIVER BASINS WAS 105 PERCENT.
APRIL PRECIPITATION ACROSS THE UPPER MISSOURI BASIN WAS ABOVE AVERAGE
TO AVERAGE. BASIN PRECIPITATION SUMMARIES FOR THE MISSOURI BASIN
INCLUDE: MILK ST. MARY, 104 PERCENT; MILK CANADA, 194 PERCENT;
LOWER MILK, 203 PERCENT; ABOVE TOSTON, 103 PERCENT; TOSTON TO
FT. PECK, 154 PERCENT.
April 2012 Upper Missouri Mean Precip Oct-Apr WY2012 Upper Missouri Mean Precip
STREAM FLOW IN THE UPPER MISSOURI BASIN IS FORECAST TO BE
NEAR AVERAGE DURING THE SPRING AND SUMMER. THE ST.
MARY RIVER IS FORECAST TO HAVE 109 PERCENT OF AVERAGE MAY-SEPTEMBER
FLOWS. RUNOFF IS EXPECTED TO RANGE AROUND 78 PERCENT OF AVERAGE
FOR THE MISSOURI BASIN ABOVE FORT PECK, MONTANA. FORECASTS FOR THE
MILK RIVER BASIN CALL FOR AROUND 145 PERCENT OF AVERAGE SPRING SUMMER
RUNOFF.
Upper Missouri May 1, 2012 Spring and Summer Streamflow Forecasts
OF THE FOUR MAJOR IRRIGATION RESERVOIRS IN MONTANA: LIMA RESERVOIR
HAD 134 PERCENT AVERAGE STORAGE, CLARK CANYON WAS HOLDING 109 PERCENT OF
AVERAGE WATER, GIBSON RESERVOIR HAD 118 PERCENT OF AVERAGE STORED
WATER, AND FRESNO RESERVOIR HAD 104 PERCENT OF AVERAGE STORED WATER.
THE MAJOR HYDROELECTRIC RESERVOIRS IN MONTANA (CANYON FERRY AND
FORT PECK) HAD MONTHEND STORAGE IN THE AVERAGE RANGE; 109 AND 112
PERCENT OF AVERAGE WATER, RESPECTIVELY.
Yellowstone Basin
STREAMS IN THE WIND RIVER BASIN ARE FORECAST TO HAVE NEAR RECORD LOW FLOWS.
THE HIGH ELEVATION SNOW PACK IN THE YELLOWSTONE BASIN WAS BELOW AVERAGE
ON MAY 1. THE SNOW PACK IN THE UPPER YELLOWSTONE BASIN WAS
82 PERCENT OF AVERAGE. THE SNOW PACKS IN THE WIND, BIGHORN, AND
SHOSHONE BASINS WERE 48, 63, AND 74 PERCENT OF AVERAGE,
RESPECTIVELY. THE SNOW PACKS IN THE TONGUE AND POWDER BASINS WERE
66 AND 46 PERCENT OF AVERAGE, RESPECTIVELY.
PRECIPITATION DURING APRIL WAS NEAR AVERAGE TO BELOW AVERAGE. THE UPPER
YELLOWSTONE RIVER BASIN RECEIVED 107 PERCENT OF AVERAGE PRECIPITATION.
WHILE THE LOWER YELLOWSTONE BASIN REPORTED 100 PERCENT OF AVERAGE.
THE BIGHORN BASIN RECEIVED 65 PERCENT OF AVERAGE PRECIPITATION
WHILE THE WIND RIVER BASIN RECEIVED 43 PERCENT OF AVERAGE.
THE LITTLE BIGHORN - UPPER TONGUE BASIN RECEIVED 87 PERCENT OF
AVERAGE AND THE POWDER RIVER HAD 90 PERCENT OF AVERAGE PRECIPITATION.
April 2012 Yellowstone Mean Precip Oct-Apr WY2012 Yellowstone Mean Precip
FORECAST STREAM FLOW IN THE YELLOWSTONE BASIN IS NEAR
AVERAGE RANGE FOR THE UPCOMING SPRING AND SUMMER. RUNOFF AT
BILLINGS, MONTANA IS EXPECTED TO BE 95 PERCENT OF AVERAGE. STREAM
FLOW FOR THE WIND-BIGHORN BASIN ABOVE ST. XAVIER, MONTANA IS
FORECAST TO BE ABOUT 52 PERCENT OF AVERAGE. FLOW IN THE
TONGUE BASIN IS EXPECTED TO BE 68 PERCENT OF AVERAGE. FLOWS IN THE
POWDER RIVER ARE EXPECTED TO BE ABOUT 64 PERCENT OF AVERAGE.
MONTHEND STORAGE AT BOYSEN RESERVOIR WAS 112 PERCENT OF AVERAGE.
STORED WATER IN BUFFALO BILL RESERVOIR WAS 136 PERCENT OF AVERAGE.
MONTHEND STORAGE WAS 104 PERCENT OF AVERAGE AT BIGHORN RESERVOIR.
Yellowstone May 1, 2012 Spring and Summer Streamflow Forecasts
Platte Basin
STREAMS IN THE NORTH AND SOUTH PLATTE BASINS ARE FORECAST TO HAVE NEAR RECORD FLOWS.
THE HIGH ELEVATION SNOW PACK IN THE UPPER NORTH PLATTE BASIN WAS
29 PERCENT OF AVERAGE ON MAY 1. THE SNOW PACK IN THE NORTH
PLATTE BASIN BELOW SEMINOE RESERVOIR WAS 40 PERCENT OF AVERAGE.
THE SNOW PACK IN THE SOUTH PLATTE BASIN WAS 30 PERCENT OF AVERAGE.
APRIL PRECIPITATION ACROSS THE PLATTE BASIN WAS MUCH BELOW AVERAGE.
PRECIPITATION DURING APRIL IN THE NORTH PLATTE BASIN ABOVE
SEMINOE RESERVOIR WAS 60 PERCENT OF AVERAGE. IN THE
NORTH PLATTE BASIN BETWEEN SEMINOE RESERVOIR AND GUERNSY RESERVOIR
PRECIPITATION WAS 49 PERCENT OF AVERAGE. THE NORTH PLATTE BASIN
BELOW GUERNSY RESERVOIR HAD LESS THAN 38 PERCENT OF AVERAGE PRECIPITATION.
THE HIGH ELEVATIONS OF THE SOUTH PLATTE BASIN HAD 57 PERCENT OF
AVERAGE PRECIPITATION WHEREAS THE PLAINS HAD 104 PERCENT OF AVERAGE
APRIL PRECIPITATION.
April 2012 Platte Mean Precip Oct-Apr WY2012 Platte Mean Precip
STREAM FLOW IN THE PLATTE BASIN IS FORECAST TO BE BELOW
AVERAGE DURING THE UPCOMING SPRING AND SUMMER.
RUNOFF FOR STREAMS ABOVE SEMINOE RESERVOIR ARE EXPECTED TO BE ABOUT
15 TO 50 PERCENT OF AVERAGE. STREAM FLOWS FOR THE NORTH PLATTE
BELOW SEMINOE RESERVOIR ARE FORECAST TO BE AROUND 22 PERCENT OF
AVERAGE. STREAMS IN THE SOUTH PLATTE BASIN ABOVE SOUTH PLATTE,
COLORADO CAN BE AROUND 25 PERCENT OF AVERAGE FLOW. FOR THE
REMAINDER OF THE SOUTH PLATTE BASIN FLOWS ARE EXPECTED VARY FROM
30 TO 50 PERCENT OF AVERAGE.
STORED WATER IN THE SOUTH PLATTE BASIN WAS 102 PERCENT OF AVERAGE
ON MAY 1. STORED WATER IN THE NORTH PLATTE BASIN WAS 127
PERCENT OF AVERAGE.
North Platte Streamflow Fcst South Platte Streamflow Fcst
