In the Pacific Northwest, water in the reservoirs, rivers and streams is usually sustained through the summer by slowly melting winter snows. But the region was unusually warm this past winter, causing most precipitation to fall as rain instead of snow. Hydrologist Julie Koeberle of the Natural Resources Conservation Service explains why this is a problem.

Koeberle: “A snowpack is a known quantity of water that we know that we can count on in the later season as opposed to rainfall which quickly moves through the system.”

And without snow as insulation, the soil dried out and the winter rain was absorbed by the dry ground instead of replenishing regional reservoirs. While snowpack levels in the past have sometimes gone up or down, scientists predict that a changing climate will increase the number of years with relatively low snowfall.

Koeberle: “This year is a classic example of what has been projected. Which is less snowpack overall and it’s starting later and leaving earlier. So winter essentially squeezed into a few months.”

The mountain snowpack that has provided water in the Pacific Northwest for generations will become increasingly unreliable as the climate warms.

Reporting credit: ChavoBart Digital Media/Jason Jackson.
Photo: Copyright protected.

More Resources
Natural Resources Conservation Service: Snow Survey (Oregon)
Oregon Basin Outlook Report (April 1, 2015)
Oregon Governor Expands Drought Declaration
Low water exposes Emigrant Lake’s past

David Appell

A regular contributor to Yale Climate Connections since 2012, David Appell, Ph.D., is a freelance writer living in Salem, Oregon, specializing in the physical sciences, technology, and the environment. His...