Perfect storm for low flows
Despite a “gangbusters” February snowpack, melting in the high country has all but ceased due to a cold, wet May.
“Snowmelt has decreased essentially across the mountains, and we’re seeing that in all the stream flows too, so flows are dropping quick,” Danny Tappa, a Boise hydrologist, said.
On Thursday, the Bureau of Reclamation decreased outflows from Jackson Lake Dam to 3,000 cubic feet per second, down from 4,000 cfs, to match slowing run-off from mountain tributaries.
Water managers strive to make sure outflow from the dam doesn’t outpace inflow from the Tetons so that the lake will fill up. Likewise, the bureau dropped the outflow from Palisades Dam from 13,000 cfs to 11,000 cfs.