Wednesday, March 13, 2019

Water supply issues could be a reality for North-Central Washington

Map of Washington state. Methow and Okanogan show as 78% chance of reaching drought conditions.

It seems unbelievable that with the exceptional cold and snow in February that state officials could actually be talking about communities facing water supply hardships. Yet, it’s true.

Maia Bellon, director of Ecology, today met with the Executive Water Emergency Committee to discuss water supply conditions in Washington. The committee is comprised of state leaders and experts in an array of areas tied to water supply.

The Methow and Okanogan basins in North-Central Washington near the Canada border, are projected to experience some water supply shortages based on current snowpack levels, soil conditions, and climate predictions.

The committee will confer in the coming weeks to determine if any action is needed to help address hardships that could be felt by communities, farms or fisheries resources. State and federal experts will continue collecting data and updating the water supply forecasts and potential hardships

Below are highlights from the most recent water supply update made by Ecology and partner experts.

Snowpack conditions
At 87 percent of normal, statewide snowpack currently ranks 11th lowest out of the past 30 years. Compared to this time over the previous five years, snowpack is lower than in 2018, 2017, and 2016, but significantly higher than 2015, which was a record snow-drought.

It is unlikely that snowpack, averaged statewide, will reach normal by early April, which is when snowpack generally peaks. It would require many feet of snow across the state. However, spring precipitation can continue to add water to existing snowpack.

Snowpack is deficient in the headwaters of the Methow and Okanogan watersheds, east of the North Cascades. River forecasts there indicate a high likelihood of below normal summer water conditions and the U.S. Drought Monitor has designated portions of Okanogan and Ferry County as being in Moderate Drought due to an extended precipitation deficit. Water supply forecasts for the Okanogan and Methow Rivers indicate a high probability that this year’s April – September runoff will be among the lowest recorded over the past 70 years.

The Walla Walla/Lower Snake regions in Southeast Washington are the only regions of the state with above normal snowpack. They benefited from the major storms that brought copious amounts of snow to California and Oregon. Lower Yakima is shy of normal, at 95 percent. The remainder of the state is below normal, generally in the 85 – 95 percent range. The Central Puget Sound is the biggest laggard, at 74 percent of normal. This area supplies Green-Duwamish, Lake-Washington/Cedar, Snoqualmie, and Skykomish basins.


February was Washington's 5th coldest since 1895. Temperatures in Eastern Washington averaged between 10 and 15 degrees below normal, an anomaly described as “staggering” by the Office of Washington State Climatologist. Since the beginning of March, the anomalies have been even larger, with some locations recording average temperatures up to 20 degrees more below normal. Western Washington has been much colder than normal as well. Since the beginning of the month, temperatures have averaged 5 – 8 degrees below normal at lower elevations and 10 degrees below normal on the Western flank of the cascades. 
NOAA climate mao that show parts of Washington with a 50% chance of warmer conditions than usual over the the next three months.

Rivers and streams

Cold temperatures means snowpack is holding strong and not melting. Numerous rivers on the west side of the state are flowing at record low or near record low levels for this time of year. Seven-day average streamflow is below normal at 84 percent of the river stations managed by the United States Geologic Surveys.

Future forecasting

Our water supply expert Jeff Marti regularly updates Ecology’s water supply forecast. You can see the full recap of current conditions and forecasting on our website.  

By Camille St. Onge, communications

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