Regional Climate Change Impacts

Snohomish, King, & Pierce Counties are working together to prepare for the impacts of climate change.

The earth’s climate is changing – we’ve all seen the signs of this in the central Puget Sound. Hotter summers. Longer dry spells. Changes in rainfall and snowpack. Climate change is largely human induced and caused by an increase in heat-trapping atmospheric gases – or greenhouse gases.

Studies indicate that the Puget Sound region – with our reliance on snowpack and high utilization of local rivers and streams for water supply and fish habitat – has been and will continue to be impacted by climate change. Climate models predict a variety of impacts to water resources in the region, including:

  • Warmer weather year-round with drier summers and wetter winters
  • Reduced snowpack and flows from snowmelt due to warmer winters
  • Increases in winter river flows and decreases in summer flows
  • Higher use of water in the summer
  • More frequent extreme weather events


To ensure the region has sufficient water in the future, Water Supply Forum members are working hard to understand and actively address potential climate change impacts. Everett, Seattle, and Tacoma have studied how climate change could affect their water systems, both in terms of supply and demand. They have also identified adaptation strategies to tackle climate change vulnerabilities.

Climate Change Impacts Studies & Resources