WENATCHEE, Wash. — Central Washington irrigators appear in good shape for summer with the remaining mountain snowpack at 107 percent of normal and streamflows forecast at normal and above.
High-mountain snow actually increased in April after a slow start earlier. Mountain snowpack in the Wenatchee region is 102 percent of normal, according to the May 1 report of the Natural Resources Conservation Service’s Washington Snow Survey Office in Mount Vernon. It’s 99 percent in the Yakima area, 120 percent in north Puget Sound, 107 percent in south Puget Sound and 99 percent in the Lewis-Cowlitz basins.
The Columbia River is a given for irrigators except for problems caused by drawdowns because of a crack at Wanapum Dam. The main concern is too fast a warmup causing the snowpack to run off quicker into the rivers and streams serving orchards and farms on the east slopes of the Cascades, said Scott Pattee, NRCS water supply specialist in Mount Vernon. Too fast a runoff means less water for irrigators in summer.
“But we would have to have temperatures considerably above normal for that to happen and lots of sunshine,” Pattee said.
At this point, snow below 3,500 feet in elevation is gone and snow above that is melting in an orderly fashion, which should sustain good flow for irrigators through the summer, he said.
“The melt curves are pretty much on track for the upper elevations,” Pattee said.
Earlier in the season, things didn’t look so rosy. The state’s snowpack was 44 percent of normal on Jan. 1 and there were concerns of the first drought since 2005.
The forecast for percent of normal for May 1 through September: Okanogan River at Tonasket, 119; Methow River at Pateros, 90; Chelan River at Chelan, 103; Entiat River at Ardenvoir, 99; Wenatchee River at Peshastin, 107; Upper Yakima at Cle Elum, 95; Teanaway at Cle Elum, 117; all lake inflows of Upper Yakima, 97; Naches River at Naches, 103; Yakima River at Parker, 101; Ahtanum Creek at Union Gap, 89; and Klickitat River near Pitt, 103.
An El Nino weather pattern appears to be developing in the South Pacific by the end of the summer which would mean warm, wet weather next winter with rain and not enough mountain snow, Pattee said.