With winter in full swing, it's time to discuss the status of Washington's water supply. It’s been a wet(ish) winter. Impacts from La Niña weather patterns came later than expected. Is the drought nearing an end? Members of Ecology’s Water Supply Availability Committee, a group of water supply experts from a variety of state and federal agencies, aren't sure yet.
Current conditions
The drought declared in April is still in effect. Experts are watching for evidence of drought recovery such as improved snowpack, streamflows, and soil moisture.
Previous forecasts predicting a colder and wetter winter haven’t come to fruition. There is added uncertainty around the temperature forecast for the upcoming months, but more confidence in above normal winter and spring precipitation.
Average statewide temperatures for the water year-to-date (October through December) were above normal (+1.9º F) tying as the 13th warmest start to the Water Year on record.
Consistent colder temperatures are necessary to support a strong snowpack. Snowpack serves as natural water storage for summer and early fall. Higher temperatures and reduced snowpack creates concerns for water supply later in August and September.
Average precipitation statewide was 108% of normal statewide. However, the statewide average can be deceiving. Eastern Washington experienced precipitation ranging from 110% to 190% of normal, while Western Washington has had areas of much below normal precipitation.
January precipitation is predicted to be much wetter, and temperatures are predicted to be slightly warmer than normal.
The climate prediction center has officially said that La Niña has arrived. However, this La Niña is weak – which means less of an impact on our temperature and precipitation. It is expected to persist through spring.
We are closely watching drought recovery in the Yakima Basin. Bureau of Reclamation reservoir storage is at 35% of average for January. This is a concerning storage level, with a gap in storage after back-back droughts in 2023 and 2024 and compounding deficits in precipitation since October 2023 for the area.
Snowpack
Snowpack started accumulating in October. Some areas had more favorable impacts from November and December storms than others.
While statewide snowpack is currently 111% percent of normal, this isn’t necessarily cause for optimism. Early season snowpack is not a good predictor of April through September streamflow. Snowpack was healthy in 2021 and 2023 before spring heatwaves resulted in early melt-off.
Streamflow
Streamflow is relatively normal across the state. There are sites above normal to the east and southeast, and a few below normal in the central areas of the state and Olympia and Tacoma areas. December average streamflows improved in most of the state. Streamflow is within normal ranges and above average in the Olympic Peninsula and northwest corner of the state. Below normal and much below normal conditions persist in the northeast.
What’s next?
We’ll continue monitoring conditions throughout the state. In the meantime, we’re still accepting emergency drought applications. Any grant applications this winter must be to address continued water supply issues from 2024 drought conditions (see Ecology's Drought response grants).