Precipitation
Reservoir
Streamflow
All the following forecasts are the 50 percent chance runoff for the June
through September runoff period. Yellowstone at Lake Outlet is expected to
yield about 420,000 acre feet (61 percent of normal). Yellowstone at
Corwin Springs will yield about 1,010,000 acre-feet (68 percent of normal).
Yellowstone near Livingston will yield about 1,150,000 acre feet (67
percent of normal). Hebgen lake inflow is estimated to be 220,000 acre feet
(72 percent of normal). See the following page for detailed runoff volumes.
================================================================================================================================== UPPER YELLOWSTONE & MADISON RIVER BASINS Streamflow Forecasts - June 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 JUN-SEP 389 408 | 420 61 | 432 451 691 | | YELLOWSTONE RIVER at Corwin Spgs. JUN-SEP 845 943 | 1010 68 | 1077 1175 1484 | | YELLOWSTONE RIVER near Livingston JUN-SEP 951 1069 | 1150 67 | 1231 1349 1721 | | HEBGEN Reservoir Inflow JUN-SEP 190 208 | 220 72 | 232 250 307 | | ================================================================================================================================== UPPER YELLOWSTONE & MADISON RIVER BASINS | UPPER YELLOWSTONE & MADISON RIVER BASINS Reservoir Storage (1000 AF) - End of May | Watershed Snowpack Analysis - June 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 32.1 34.6 35.8 | MADISON RIVER in WY 6 28 62 | HEBGEN LAKE 377.5 355.5 298.8 309.8 | YELLOWSTONE RIVER in WY 8 36 49 | ================================================================================================================================== * 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.