The authors say the convergence gives salmon less time to recover from the stress of warm water before the stress of low water hits -- 20 to 30 days less time.
The study was based on stream flow records between 1950 and 2010 from 22 sites in Oregon, Washington, California, Nevada, Montana and Idaho.
Researchers from Oregon State University, the U.S. Forest Service, and the U.S. Geological Survey cited other research indicating climate change is behind the convergence, producing lower snowpacks in winter and earlier snowmelt in spring.
The study appears in the journal Hydrobiologia.
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