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Wyoming Basin Outlook Report for
UPPER YELLOWSTONE & MADISON RIVER BASINS as of March 1, 2012

Snow Snow water equivalent (SWE) is at 86% of average in the Madison drainage. SWE in the Yellowstone drainage is at 96% of average. See the Basin Summary of Snow Course Data at the front of this report for details. Precipitation Last month precipitation in the Madison and Yellowstone drainage was about 100% of average (117% of last year). The 5 reporting stations percentages range from 72-135% of average. Water-year-to-date precipitation is about 107% of average (93% of last year s amount). Year to date percentage ranges from 83-06%. Reservoir Ennis Lake is storing about 29,600 ac-ft of water (72% of capacity, 94% of average or 106% of last year s volume). Hebgen Lake is storing about 293,500 ac-ft of water (78% of capacity, 111% of average or 101% of last year s volume). Detailed reservoir data is shown on the following page and on the reservoir storage summary at the beginning of this report. Streamflow The 50% exceedance forecasts for April through September are about average for the basins. Yellowstone at Lake Outlet is 795,000 ac-ft (99% of average). Yellowstone at Corwin Springs will yield around 1,950,000 ac-ft (99% of average). Yellowstone near Livingston will yield around 2,230,000 ac-ft (98% of average). Hebgen Reservoir inflow is 450,000 ac-ft (89% of average). See the following page for detailed runoff volumes.

Streamflow Forecasts

UPPER YELLOWSTONE & MADISON RIVER BASINS
Streamflow Forecasts - March 1, 2012

 <==== Drier === Future Conditions === Wetter ====> 
Forecast Pt============ Chance of Exceeding * =========== 
   Forecast90%70%50% (Most Prob)30%10%30 Yr Avg
   Period(1000AF)(1000AF)(1000AF)(% AVG.)(1000AF)(1000AF)(1000AF)

Yellowstone R at Yellowstone Lake
APR-JUL 490       560       605       103       650       720       590      
APR-SEP 645       735       795       99       855       945       805      
Yellowstone R at Corwin Springs
APR-JUL 1360       1550       1670       101       1790       1980       1650      
APR-SEP 1580       1800       1950       99       2100       2320       1970      
Yellowstone R at Livingston
APR-JUL 1520       1750       1910       101       2070       2300       1900      
APR-SEP 1770       2040       2230       98       2420       2690       2280      
Hebgen Reservoir Inflow (2)
APR-JUL 285       325       350       89       375       415       395      
APR-SEP 370       420       450       89       480       530       505      

    * 90%, 70%, 30%, and 10% chances of exceeding are the probabilities that the
       actual flow will exceed the volumes in the table.

    (1) - The values listed under the 10% and 90% Change of Exceeding are
            actually 5% and 95% exceedance levels.
    (2) - The value is natural flow - actual flow may be affected by upstream
            water management.



Reservoir Storage

UPPER YELLOWSTONE & MADISON RIVER BASINS
Reservoir Storage (1000AF) End of February

 Usable************* Usable Storage *************
Reservoir Capacity This Year Last Year Average

ENNIS LAKE 41.0      29.6         27.8          31.4        
HEBGEN LAKE 377.5      293.5         291.0          265.2        



Watershed Snowpack Analysis

UPPER YELLOWSTONE & MADISON RIVER BASINS
Watershed Snowpack Analysis - March 1, 2012

 Number ofThis Year as Percent of
Watershed Data Sites Last Year Normal

MADISON RIVER in WY 8               80               86              
YELLOWSTONE RIVER in WY 11               86               96              

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or Write:
D. Lee Hackleman, Water Supply Specialist
Natural Resources Conservation Service
100 East B Street
Casper, WY 82601
(307) 261-6481

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