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Jet Stream Divides Idaho

Boise– The Natural Resources Conservation Service has released the second water supply outlook report for the 2018 water year. 

Precipitation since the water year started on October 1, 2017, varies across the state with watersheds ranging from 70 to 130% of normal.

“A winter like this one is what makes Idaho unique and interesting,” said Ron Abramovich, Water Supply Specialist with the Idaho Natural Resources Conservation Service. “The weather pattern has been pretty consistent since October, with the jet stream streaking across northern Idaho and then dipping along the Continental Divide. This brings moisture to the basins north of the Salmon River, while central and southern Idaho are drier than normal.”

Currently, the highest snowpacks are in the Clearwater basin where collectively, they are 110% of normal. The lowest snowpack continues to be in in the Owyhee basin, which is 35% of normal. 

“With more than half the winter behind us, many reservoir operators are taking a wait-and-see approach toward releasing water,” Abramovich said. “Good reservoir storage will provide a buffer if snowpacks remain below normal across southern Idaho.”

Based on the current snowpack and reservoir storage, water supplies may be marginal in the Big Wood, Big Lost, and Little Lost basins. Elsewhere, there is plenty of water in the reservoirs that will help provide an adequate irrigation supply in the Boise, Upper Snake, Bear, Oakley, Salmon Falls and Owyhee basins. However, more snow or a wet spring would help reduce the risk of irrigation shortages.

For information on specific basins, streams, and reservoirs, please view the full report online at February Water Supply Outlook Report.