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Climatologist: Wetter winters, drier summers ahead

Washington’s state climatologist says the Pacific Northwest "will be a different place" over the next several decades as freezing levels rise. Climate change projections are for higher river flows and more flooding in winter and maybe more extreme events in summer.

SEATTLE — Winter temperatures in the Pacific Northwest will increase during the next several decades, and the best climate estimates show “this will be a different place,” according to Nicholas Bond, Washington state climatologist.

“We have to anticipate a range of outcomes. We might luck out and have just a few degrees more,” Bond told a Sept. 6 seminar on climate change.

Bond is a principal research scientist with the Joint Institute for the Study of the Atmosphere and Ocean at the University of Washington and an affiliate associate professor with the Department of Atmospheric Sciences.

He said the changes in annual precipitation in Oregon, Washington and Idaho will be diverse, and the seasonality of precipitation will likely change. Winters will be wetter and summers will probably be drier.

Climatologists’ projections — not predictions, he said — show small changes over the next decade, more by 2040 and still more by the end of the century. That trend reflects a consensus among researchers, but not a unanimous opinion.

Snowpack, so vital to the region, will show different trends at different intervals.

“Everything is local,” he said. “One size doesn’t fit all.”

Overall, the freezing level in the region’s mountains will rise, meaning more winter precipitation will fall as rain instead of snow. That will have major effects in the amount of runoff from the rain that falls during the winter and from snowmelt in the summer.

Bond projected higher winter flows for major Pacific Northwest rivers and more winter floods. There may also be more extreme weather events in summer, “though we’re just starting to look at that,” he said.

“We’re making better models, but they’re imperfect. There’s always a range of outcomes,” he said.



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