Watching the water supply

An image showing a group of people on a mountainside covered in snow. Rainier in background.

Snow is piling up at Paradise on Mt. Rainier. Photo: National Park Service webcam.

It’s a new year and a good time to check in on our statewide water supply. Winter usually puts less pressure on our water supply because of reduced demand for water in homes and less agricultural irrigation. But communities and farms are already starting to plan for the drier and warmer months — and experts are watching the conditions closely.

Looking back at 2016

For Washington state as a whole, 2016 was a slightly warmer, wetter-than-normal year. Temperature-wise, the state was 1 to 2 degrees warmer than average annually, and March through May tied 1992 for record warmth.
The balmy spring caused our snowpack to melt at record rates. In early April, the state snowpack was slightly above normal. By late May, it was less than 50 percent of normal. This raised some concern that water supplies might be pinched later in the summer, but a switch to wetter conditions and more moderate temperatures in June and July made things manageable. Still, there were some watersheds in southwest Washington where dry conditions caused total runoff during the spring and summer to be even lower than 2015 — a drought year.
This fall, the warmth returned along with long stretches of rainy days. Averaged statewide, October and November were the second-warmest on record (3.3 degrees above normal) and wettest on record (6.61 inches above normal). The pattern changed in December, though, when cooler, drier weather swept in. Most of the state was chilly — with many areas a few degrees below normal — for the first few weeks of the month.

Status of water supplies

 Let’s take a closer look at water supply as of Jan. 5 and forecasts for the future:

View of a snow covered landscape, trees in distance, cloudy sky with sun shining through.

The sun peeks out over a snowy scene on Hurricane Ridge. The Olympic Mountains have 126 percent of normal snowpack for this time of year. Photo: National Park Service webcam

Weather and outlook | Looking ahead, state climatologists are expecting La Niña conditions (cool and wet) to shape regional climate, but there’s a good chance we’ll switch into neutral conditions (neither La Niña nor El Niño) later this winter. Forecast models aren’t clear on temperature heading into spring, but they are predicting wetter-than-normal weather. Beyond spring, the forecast models aren’t saying much.
Mountain snowpack | Mountain snow is critical because it serves as a reservoir during spring and summer, gradually melting and feeding rivers and streams. Mountain snowpack got a late start this year but is currently looking good. The lower Columbia, central Puget Sound and Olympic regions, in particular, are doing great with more than 125 percent of normal snowpack for this time of year. The mountains near Spokane are somewhat behind schedule, but they’re still looking decent with 77 percent of normal snowpack.
Rivers and streams | Experts are seeing typical conditions for rivers and streams. Daily streamflows are mostly in the normal range. Flows are dropping below normal during cold snaps, when snowmelt stops.
Agriculture | The U.S. Bureau of Reclamation reports that storage levels at the five reservoirs in the Yakima River basin, a major agricultural center, are at 107 percent of normal. Precipitation from October to the end of December is about 94 percent of normal in the Yakima region.
Drinking water | Drinking water supplies in the state’s big cities are in good shape. At the beginning of September, Everett’s water storage was 110 percent of normal for that time of year. Seattle’s combined reservoir storage is also above normal for this time of year. Tacoma reports that both precipitation and snowpack levels are above normal at the Lynn Lake monitoring site near the Howard Hanson Reservoir.

How you can help

We all have a role to play in conserving water, even in winter! Here's one way you can make a difference:
  • Insulate outdoor spigots to prevent them from freezing and bursting. If you have an outdoor garden hose, remove and drain it. This video from the Saving Water Partnership has more information.
For more tips, visit our water conservation page.