Upper Snake Reservoir Operations October 13, 2015 Henry’s Fork Watershed Council Upper Snake Reservoir Operations October 13, 2015

41% of Capacity

88% of Capacity

29% of Capacity

Coordinated Forecast Month-July Snake River nr Heise, ID January Forecast 109% (4,130 KAF) 78% of Average Precipitation February Forecast 101% (3,625 KAF) 77% of Average Precipitation March Forecast 95% (3,256 KAF) 41% of Average Precipitation April Forecast 78% (2,515 KAF) 59% of Average Precipitation May Forecast 63% (1,800 KAF) 136% of Average Precipitation

2015 Water Year-to-Date Precipitation

WY2015 Percent 30yr Avg. Runoff Snake River nr Heise, ID April-July Forecast 78% (2,515 KAF) April-July Observed 85% (2,740 KAF) WY2015 Observed 91% (4,530 KAF) Henrys Fork nr Island Park, ID April-July Forecast 47% (102 KAF) April-July Observed 59% (127 KAF) WY2015 Observed Runoff 68% (319 KAF)

2016 Temperature Outlook

2016 Precipitation Outlook

Conclusions System carryover is lower than in 2014 but good overall Good probability of high system storage for 2016 allocations Minimum winter flows at most facilities Not expected to change unless flood control operations are needed Current winter forecasts lack confidence Abnormal ocean temperatures Long-lead forecast uncertainty