The annual assessment of water year impacts on the Pacific Northwest is an ongoing project with the goal of better understanding the impacts of events and conditions of the previous water year on agricultural production, drinking water supply, hydropower, fisheries, recreation, forestry and other sectors dependent on natural resources. Each year, we review the significant weather events and climate conditions of the water year, capture the water year impacts, facilitate knowledge sharing among scientists and practitioners and provide a forecast for the upcoming water year.

Every year this project consists of two main components — a water year meeting, held in the fall, and a written assessment, published in late winter. The two main components of this project are discussed in more detail below.

Annual Water Year Recap & Outlook Meeting

For nearly two decades, researchers, water and resource managers and organizations working to integrate research and water management in Oregon and Washington have held a joint Water Year Recap and Outlook meeting. The water year meeting gathers practitioners to share their experiences during the water year and to discuss the implications of the forecast for the upcoming water year. A separate but similar meeting in Idaho is also held each year. In coordination with these annual water year meetings, an Annual Pacific Northwest Water Year Impacts Survey is used to collect information about water year impacts on multiple sectors.

This annual event is co-hosted by the Office of the Washington State Climatologist, the University of Washington Climate Impacts Group, and the National Oceanic and Atmospheric Administration (NOAA) National Integrated Drought Information System (NIDIS) with input from a planning committee. Planning committee participation varies from year-to-year. The 2022 planning committee includes representatives from the Nez Perce Tribe Water Resources Division, Oregon State University’s Oregon Climate Service, the WA Department of Ecology and USDA Northwest Climate Hub.

Water Year Assessment

Weather and climate conditions, impacts, and response actions are summarized in the annual Pacific Northwest Water Year Impacts Assessment based on weather and climate observations as well as information collected in the meeting discussions and survey. The Oregon State Climatologist and Idaho Department of Water Resources contribute to the annual report, with support from National Integrated Drought Information System (NIDIS) and state and regional water resource partners.

Testimonial for the Water Year Assessment Work

“My municipality uses a surface water source for our intake into the water treatment plant. Part of my role is to monitor surface water discharge rates and inform stakeholders of any curtailment measures needed due to minimum river flows not being met. This is especially important during the end of summer when water use spikes and river levels slow. I am using the Pacific Northwest Water Year 2024 Impacts Assessment as a source for summer water supply outlook communications that will help to inform my organization around any potential curtailment measures for the upcoming warm seasons. I use data from the Impacts Assessment to describe how the 2024 water year impacted our 2024 summer water use and supply, and merge this with data from the NIDIS Drought Outlooks to set expectations of our water supply as we head into summer.

The Water Year Impacts section of the report also helps me understand how other sectors in addition to water purveyors were impacted by drought and the responses that they took. Thank you for supplying this helpful report.” – Jason Hoye, water conservation specialist in Oregon

A summary of each water year meeting and assessment since 2020 is below

Water Year 2024 Impacts

The fifth Pacific Northwest Water Year Impact Assessment chronicles the water year, its impacts, and how people responded across Washington, Oregon, and Idaho during the 2024 water year (October 1, 2023-September 30, 2024). Over the 2024 water year, PNW temperatures were tied as the 4th warmest in the 129-year record, with anomalies +1.4°F above the 1991-2020 normal. The 2024 water year was also warmer than six of the last eight water years. Water year precipitation was below normal in Washington and Idaho and near-normal in Oregon.

2024 Water Year Assessment

Water Year 2023 Impacts

Over the 2023 water year (October 1, 2022-September 30, 2023), drought worsened across most of Washington, the Idaho panhandle, and northwestern Oregon. In contrast, drought improved or was eliminated in southern Idaho, southeastern Oregon, and south central Oregon.

The recently-released assessment covers the impacts of worsening drought during the last water year and the rapid snowmelt and heatwave in May 2023. These impacts included reduced water availability and associated voluntary water conservation measures, fisheries closures and reduced hydropower generation.

2023 Water Year Assessment

Water Year 2022 Impacts

The 2022 water year was characterized by abrupt transitions in weather – from an abnormally dry winter, to an abnormally wet spring, and back to an abnormally dry summer.

Overall, temperature averages and precipitation totals across Idaho, Oregon and Washington were close to normal during the 2022 water year. However, there was regional variability, especially in precipitation. Drought conditions improved in most areas of the Pacific Northwest but persisted in central and south-central Oregon as well as southern Idaho. There was seasonal variability as well: spring was wetter and colder than normal across the Pacific Northwest, and summer was the warmest and fifth driest on record (compared to 1991-2020 averages).

Agriculture, forestry, drinking water, fisheries and other sectors were affected by both the abnormally dry and abnormally wet conditions. Abnormally dry conditions reduced streamflow, surface water availability and hydropower generation. Abnormally wet conditions reduced drinking water quality, delayed planting and harvest, limited access to recreation and more.

2022 Water Year Assessment

Water Year 2021 Impacts

Overall, the 2021 water year was warmer and drier than normal for the Pacific Northwest. As a whole, the 2021 water year tied 2016 as the fifth warmest and tied 1915 as the 17th driest (83% of normal precipitation) on record (since 1895; NOAA NCEI).

Agriculture, forestry, drinking water, fisheries, and recreation sectors were affected by the abnormally dry conditions. Impacts included less surface water available for agriculture and fishes, water rights restrictions, reduced crop yields, plant stress, tree mortality, and voluntary water restrictions. Impacts were particularly widespread in central and southern Oregon, eastern Washington, and several river basins in Idaho. The assessment details the impacts and responses to these impacts.

2021 Water Year Assessment

Water Year 2020 Impacts

In water year 2020, most of Oregon experienced a significant drought with impacts that included widespread wildfires, agricultural and livestock losses and limited outdoor recreation. Drought in Washington and Idaho was not as widespread or significant, with localized drought in only a few basins in south-central Idaho and east of the Cascade Mountain crest in central Washington. Washington and Oregon also experienced major flood events in February. These impacts and others are highlighted in the assessment.

2020 Water Year Assessment