Voice of the Mid-Columbia | Kennewick, Pasco and Richland, Wash. |
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closeThe Columbia River Basin leads the state's snowpack percentages because of recent storms, but Washington's mountain snowpack is no better than average.
Scott Pattee, a water supply specialist with the U .S. Department of Agriculture's Natural Resources Conservation Service, said Friday that data from more than 100 collection sites across the state confirm that the snow depth and water content is about what it usually is in the dead of winter.
"For all those residents who have been digging out their driveways and sidewalks for the past month, the notion of an average snowpack must seem like pure hydrological nonsense," said Pattee, whose office is in Mount Vernon.
Surveys at high-elevation sites help water managers assess supply for the summer and aid in stream flow forecasts, he noted.
"Typically, 50 percent of the total annual snow accumulation has fallen by mid-January," Pattee said. "Areas with less snow now will most likely have less runoff in spring and summer, assuming typical weather patterns continue."
Pattee said the big snows of December helped reduce a previous statewide snowpack deficit by nearly 80 percent. Before the storms hit, the snowpack was between 24 percent to 40 percent of normal.
"In just a few weeks, we've closed the gap and now stand at 106 percent statewide," he said.
Pattee said December's first snows were mostly fluff, lacking significant moisture.
"That dry stuff is pretty much all gone, but it was a big benefit that the snow was still dry, because it sucked up all the water when the rain came. And that increased the density," he noted.
Some basins exceeded average snowpack, while others were below normal.
The Columbia River Basin was 128 percent of average, while Central Puget Sound was 121 percent. Other basins reporting near-average snowpack include the Spokane River basin at 97 percent and the Yakima River basin at 99 percent.
Underperformers include the Upper Columbia River Basin at 77 percent; the North Puget Sound area at 82 percent; and the Olympic Peninsula at 76 percent of average.
Pattee said some cold weather and added snows will help keep the water on the mountains until spring, when warming weather will release it to lower elevations.
Early-season water supply forecasts for the spring and summer vary from 74 percent of average in the Okanogan River to 106 percent in the Cedar River at Cedar Falls, based on current mountain snowpack, precipitation and predicted long-range weather patterns.
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