All the snow has turned to water
Christmas days have come and gone
Broken toys and faded colors
Are all that's left to linger on
- John Prine - Souvenirs
Water year 2026, which began on October 1, 2025, has ricocheted between extremes. Beginning with record‑low reservoir levels in the Yakima Basin and the first‑ever curtailment of senior Yakima River water rights, winter then delivered major flooding across much of the state, long stretches of warm and relatively dry weather with below‑average snowpack, a late‑season blast of mountain snow, and finally a return to warm, rainy conditions and more flooding as winter ended. I’ll leave it to someone who has taken a statistics class in the last 40 years to determine whether this is normal, abnormal, or the new normal. This article provides a brief update on current conditions, a blow‑by‑blow account of fall–winter events, and forecasts (likely wrong) for the remainder of the water year.
Snowpack in Washington
We start with snowpack. Most rivers in Washington have snowmelt‑dominated hydrographs, unlike monsoonal climates that receive substantial summer rainfall. Snowpack, measured as snow water equivalent (SWE), is a key indicator used to predict summer streamflows, and the timing and rate of snowmelt runoff largely determine water supply availability heading into the dry season.
As of mid-March, snowpack (in Snow Water Equivalent or SWE) ranged from 54 to 74 percent of average for most basins in the state, with northern and northeastern Washington as high 85 percent.
March 1st SWE looked much more dire. The early March snowstorm brought average across the state about 20% closer to average.
In the Yakima Basin, this storm should increase water supply for proratable (1905) irrigators and delay the date when the Yakima Project shifts to storage control. The next Yakima Project forecast is scheduled for release on April 9th.
The statewide SWE plot above (NRCS AWS Plot) illustrates the key events—and non-events—of the fall-winter period in water year 2026. The atmospheric river in December erased the already meager early‑season snowpack. Starting from that deficit, SWE accumulation from mid‑December to mid‑January tracked above average but never closed the gap, topping out at roughly two‑thirds of normal. From mid‑January until the March snowstorm, SWE gains stayed well below average, and by early March it was clear that no realistic scenario would allow SWE to reach its median annual peak of 30.2 inches (typically observed around April 5).
The March storm added about four inches of water content to the statewide snowpack in just four days—its largest single accumulation event of the year—but the boost was short‑lived. Warm rains quickly removed roughly half of that new snow and triggered another round of flooding, significant but less severe than the December event. As of this writing, SWE stands at about 54 percent of median. The projection curves on the right show potential SWE trajectories for the remainder of the season, and none approach the median peak.
Precipitation
Clearly, total water‑year precipitation is not the issue (see NRCS plot at left). With the exception of the southeastern corner of Washington, all basins in the state are near or above average for the year. The NRCS plot below shows the rate of precipitation accumulation since October 1, averaged statewide. Precipitation from the late‑December atmospheric river was roughly equal to the combined total for January, February, and early March. The mid‑March rise initially reflected new snow accumulation, which was again followed by warm rains that melted much of it. The blue curve shows 2015 precipitation—another rain‑dominated winter. As in 2015, we may see drought declarations this year despite above‑average winter precipitation.
Temperature
Clearly, temperature was a problem. NOAA reports that the four‑month period from November through February was the warmest on record (Climate at a Glance | National Centers for Environmental Information (NCEI)). The plot below, showing temperatures averaged across Washington, highlights several periods of near‑record warmth (the black curve). The atmospheric rivers—formerly called “pineapple expresses” due to their tropical origins—brought warm air along with heavy rain. The December flood event appears clearly as a spike in temperature, and the March snow event quickly shifted from below‑average temperatures to a warm, rain‑driven system. For comparison, 2015 temperatures (the green curve) are also shown. As in 2015, stretches of unusually warm weather paired with rain rather than snow led to well‑below‑average snow water equivalent accumulation.
Streamflow: Where Has All the Snowpack Gone?
Runoff for water year 2026 in Washington ranges from near normal to about 250% of normal (see plot below). This reflects the combination of normal overall precipitation, unusually high temperatures, and multiple atmospheric river events—and is essentially the inverse of the limited snowpack.
A Yakima Basin Centric Look at Water Supply For 2026
If there was a winner in the December flood event, it was irrigated agriculture in the Yakima basin. A couple of weeks in December are the difference between the proratable irrigators expecting to receive about half their full supply and something much more dire.
Before the extreme December rain and flood event, Yakima Basin reservoirs had been drawn down to record low levels due to water shortages the last two years. In that one storm cycle storage grew from less than 25% of capacity to greater than 60%, an increase of about 400,000 acre feet. The same storm washed away most of the meager snowpack that had accumulated in November and early December. The March snow followed by rain events finished the job, by adding another 125,000 acre feet to storage, and as of March 28th, the five basin reservoirs are 91% full (140% of average) and releasing some water.
Storage in the 5 Yakima Basin Reservoirs,
Water Year 2026
Hydromet Pacific Northwest Region | Bureau of Reclamation
That all sounds good, but despite nearly full reservoirs, the Yakima Basin is still expecting another year of short water supply for both irrigation and fish. The late‑March situation looks similar to 2015: full reservoirs paired with minimal snowpack. On March 6 (before the March snowstorm), the Bureau of Reclamation estimated that proratable (1905) irrigation rights would receive 44% of a full supply—similar to last year, though last year’s shortages were driven more by low reservoir storage than by lack of snowpack. The April estimate from Reclamation is scheduled for release on April 9.
The graph below shows the statistical projection of SWE in the Yakima Basin. The range reflects different scenarios of potential late‑season snowpack accumulation as well as temperature‑ and rainfall‑driven variations in snowmelt runoff. Rapid runoff would reduce water supply, given already full reservoirs and the portion of runoff that cannot be captured. The Yakima Project’s storage system was designed with the expectation that snowmelt would continue well into the irrigation season before drawing on stored water. In the extreme low‑snowpack year of 2015, reservoirs began drafting in April, and proratable irrigators received 46% of their full supply.
Water Year 2026 SWE and Projection (NRCS) AWS Plot
Below: Water Year 2026 SWE compared with other recent drought years. Either low snowpack or low carry over reservoir storage can cause prorationing of 1905 water rights. Compare 2025 (moderate snowpack and minimal carry over) with 2015 (full reservoirs and negligible snowpack.
NRCS AWS Plot
What Next?
The stage is set. Snow water equivalent is about half of median, and recovery to average at this point is exceedingly unlikely. Spring temperature and precipitation will determine how low flows drop in unregulated streams and how quickly reservoir storage is depleted where it exists. In the Yakima, the rate of snowmelt will also influence how deep prorationing becomes.
Ecology’s Water Supply Advisory Committee will meet monthly to evaluate whether water supply estimates meet the hydrologic threshold for drought. Per the WSAC webpage, drought conditions require two elements:
- Hydrologic threshold – An area is receiving, or is projected to receive, less than seventy-five percent of normal water supply.
- Hardship threshold – Water users and the environment are or are expected to experience undue hardship. This Committee advises on the hydrologic threshold. See: RCW 43.83B.405 and WAC 173-166-050.
Notably, the criteria do not use the word “dry” or reference precipitation. The fact that water year 2026 has received above‑average precipitation will not drive the determination. In the Yakima Basin, drought declarations have been issued in recent years when proratable irrigation rights (about half the rights in the basin) are expected to receive less than 75% supply—a near certainty this summer. Elsewhere, drought declarations also seem likely as snowpack melts off.
Conclusion
Now that the Winter of Our Discontent has ended, what will spring and summer of water year 2026 bring? Given the rapid runoff of the March snowfall, major flooding may well be followed by drought declarations. In basins with reservoir storage such as the Yakima, snowpack—“the sixth reservoir”—is rapidly draining even as the physical reservoirs fill. A full water‑supply year in the Yakima requires abundant spring runoff to meet early irrigation demands before transitioning to reservoir releases in summer. Reclamation’s April forecast will provide more detail, but some level of prorationing for the 1905 users is almost certain. In basins without reservoir storage, drought declarations seem likely depending on the rate of snowmelt and spring precipitation. A big flood in December doesn’t do much for summer streamflow.
There are some bright spots (unless you are a ski area manager). Across Washington, considerable work has been done to increase river–floodplain interaction and reduce the human costs of inundation. Decades ago, a forward‑looking Yakima County Commissioner told a room full of disgruntled floodplain residents, “We are not interested in solutions that increase flooding problems downstream.” Today, the era of dike wars—solving problems on one side of the river by worsening them on the other—has largely been replaced by land acquisitions, dike removals and setbacks, and restoration of side channels. These actions help dampen flood waves, reduce peak flows, and increase base flows by shifting the hydrograph to the right. Beyond reducing flood damage, they restore habitats critical for cold‑water fish by improving access to food‑rich, thermally moderate, slow‑water environments essential for juvenile salmonids. While December floodwaters highlighted where further work is needed, places like the lower end of the Kittitas Valley upstream of Yakima Canyon passed floodwaters with minimal damage thanks to multi‑agency efforts to let the floodplain function naturally. The late‑March flood pulse will also provide a useful test of how long habitat and flow benefits persist into summer.
Another bright spot in the Yakima Basin is the operation of the recently completed juvenile fish passage facility at Cle Elum Lake. High water levels have allowed the structure to function as intended, supporting timely outmigration of Sockeye Salmon before summer temperatures rise. The facility was designed to operate even when the reservoir is below full pool. In addition, the increased streamflow from the March storm arrived at an opportune time for anadromous fish migration, whereas the December flood was too early to be beneficial.
The information in this article was derived from several publicly available sources including:
Department of Ecology Water Supply Advisory Committee
Department of Ecology - Committees, Boards, and Workgroups
US Bureau of Reclamation Yakima Project
Hydromet Pacific Northwest Region | Bureau of Reclamation
Northwest River Forecast Center
Northwest River Forecast Center - ESP Natural Forecast
NOAA National Centers for Environmental Information
National Centers for Environmental Information (NCEI)
Natural Resources Conservation Service
Washington SNOTEL Snow/Precipitation Update Report
