Cool weather, fresh round of snow ease local water worries

The wet, cool weather of recent weeks has helped boost the mountain snowpack, reducing the chance that the Seattle area will face water shortages this summer.

"We've had some pretty good increases, and it gives us a good shot at reaching our [reservoir] refill targets," said Tom Fox, who heads water management at Seattle Public Utilities.

The Seattle-area watersheds of the Cedar and Tolt Rivers have bounced back from having less than half of their seasonal averages in March to more than 60 percent of average now.

Statewide, the average snowpack has jumped from 65 percent on March 8 to more than 80 percent of normal as of this week.

The snowpack, as it melts through the spring and summer, is crucial to providing water for Seattle and other cities, irrigating crops, moving salmon downstream and generating hydropower.

This has been a quirky water year. It began with an abundance of fall snow, followed by a warm winter when some precipitation fell as rain at higher elevations and some storms largely missed the Cascade drainages west of Seattle.

But the recent cool weather has brought fresh snow, including a Friday storm that added several feet to some higher-elevation locations.

Seattle City Light, which turns snowmelt into hydropower, says the small snowpack will cause a sizable loss of revenue. Earlier in the spring, the utility said power sales would be $88 million below forecast, and the shortfall since then has edged down only slightly.

"We're still looking at a sizable hole compared to normal," said Scott Thomsen, a spokesman for Seattle City Light.

On March 22, the Seattle City Council approved a surcharge that will be added to ratepayers' bills to create a fund that can be tapped when power sales don't meet forecasts. The temporary surcharge, 4.5 percent, is scheduled to start May 1 and remain in effect through December.

In the Yakima Basin, where the snowpack helps supply irrigation water for fruits, vegetables and other crops, the late-season snow has helped out. The lower Yakima basin now has 99 percent of normal snowpack and the upper basin is at 72 percent.

"This has been welcome news. We were on a pretty bad skid through much of the winter, and this helped put the brakes on that," said Chris Lynch, a hydrologist with the federal Bureau of Reclamation.

More cool weather is forecast in the days ahead, and that should further strengthen the snowpack by delaying some of the melt and possibly adding fresh snow.

The future of the snowpack is a major topic of study for climate-change scientists, who predict that warming weather will bring more rain to lower elevations and substantially reduce the amount of water available from the annual melt.

Hal Bernton: 206-464-2581 or hbernton@seattletimes.com