A new study adds to a growing chorus of data that show that in a warmer world, Oregon could see more floods in winter and more droughts in summer.



Oregon State University researchers simulated the effect of 2 degree Celsius increase on snow in the Cascade Range. Their findings -- published this month in the journal Hydrology and Earth System Sciences -- reveals that as more precipitation falls as rain instead of snow, peak snowpack in the McKenzie River watershed will drop an average of 56 percent.



The watershed's low-elevation maritime snowpack accumulates snow close to the coast, making it particularly vulnerable to temperature shifts, said Eric Sproles, lead researcher for the study.



"A slight increase in temperature changes that maritime snow into rain," Sproles said. "This isn't a change in the total amount of precipitation, this is a big change in the phase this precipitation is delivered."



The McKenzie River originates in the high Cascades, and eventually joins the Willamette. It supplies drinking water to more than 200,000 area residents, and is the sole source of water for Eugene.



The researchers also estimated average date of peak snowpack in spring will be about 12 days earlier by midcentury, which will require changes in state management of the water supply. They also found that the elevation from about 3,300 feet to 4,900 feet will lose the greatest volume of stored water, and those elevations could lose more than 80 days of snow cover a year.



Maritime snow comprises 10 percent of the Earth's seasonal snow cover, and snowmelt is a source of water for more than one billion people.



"This is not an issue that will just affect Oregon," said Anne Nolin, a professor in the College of Earth, Ocean, and Atmospheric Sciences at Oregon State, and co-author of the study, said in a statement. "You may see similar impacts almost anywhere around the world that has low-elevation snow in mountains, such as in Japan, New Zealand, Northern California, the Andes Mountains, a lot of Eastern Europe and the lower–elevation Alps."



--Soumya Karlamangla

