Precipitation
Reservoir
Streamflow
All the following forecasts are the 50 percent chance runoff for the April through September runoff period. Yellowstone at Lake Outlet is expected to yield about 52,000 acre feet (66 percent of normal).
Yellowstone at Corwin Springs will yield about 1,315,000 acre-feet (68 percent of normal). Yellowstone near Livingston will yield about 1,515,000 acre feet (68 percent of normal). Hebgen lake inflow is
estimated to be 415,000 acre feet (85 percent of normal). See the following page for detailed runoff volumes.
================================================================================================================================== UPPER YELLOWSTONE & MADISON RIVER BASINS Streamflow Forecasts - January 1, 2000 ================================================================================================================================== | <<====== Drier ====== Future Conditions ======= Wetter =====>> | | | Forecast Point Forecast | ==================== Chance Of Exceeding * ====================== | Period | 90% 70% | 50% (Most Probable) | 30% 10% | 30-Yr Avg. | (1000AF) (1000AF) | (1000AF) (% AVG.) | (1000AF) (1000AF) | (1000AF) ====================================================================|=======================|===================================== YELLOWSTONE at Lake Outlet APR-SEP 340 447 | 520 66 | 593 700 792 | | YELLOWSTONE RIVER at Corwin Spgs. APR-SEP 948 1166 | 1315 68 | 1464 1682 1937 | | YELLOWSTONE RIVER near Livingston APR-SEP 1041 1323 | 1515 68 | 1707 1989 2241 | | HEBGEN Reservoir Inflow APR-SEP 315 374 | 415 85 | 456 515 486 | | ================================================================================================================================== UPPER YELLOWSTONE & MADISON RIVER BASINS | UPPER YELLOWSTONE & MADISON RIVER BASINS Reservoir Storage (1000 AF) - End of December | Watershed Snowpack Analysis - January 1, 2000 ================================================================================================================================== Usable | *** Usable Storage *** | Number This Year as % of Reservoir Capacity| This Last | Watershed of ================= | Year Year Avg | Data Sites Last Yr Average ========================================================================|========================================================= ENNIS LAKE 41.0 28.9 33.6 33.7 | MADISON RIVER in WY 9 56 73 | HEBGEN LAKE 377.5 344.8 331.5 246.8 | YELLOWSTONE RIVER in WY 11 62 75 | ================================================================================================================================== * 90%, 70%, 30%, and 10% chances of exceeding are the probabilities that the actual volume will exceed the volumes in the table. The average is computed for the 1961-1990 base period. (1) - The values listed under the 10% and 90% Chance of Exceeding are actually 5% and 95% exceedance levels. (2) - The value is natural volume - actual volume may be affected by upstream water management. (3) - Forecasts produced in cooperation with Alberta Forecasting Staff Canada