WENATCHEE, Wash. — Recent storms boosted Washington’s mountain snowpack by 8 percent, but forecasters say it won’t alter the arrival of an early spring runoff.
“We would need four more storms like this to make any real impact,” Scott Pattee, state water supply specialist, said after the first storm March 9. The second storm, March 12 and 13, brought an inch of snow to Wenatchee and some other east slope towns and much more in the mountains. The statewide snowpack increased from 100 to 108 percent of normal.
It helps but doesn’t lessen chances that warmer weather will melt much of the remaining snowpack about a month earlier than desired, said Pattee in the Washington Snow Survey Office of the USDA Natural Resources Conservation Service in Mount Vernon.
That’s a worry for farmland irrigators, particularly in the Yakima Basin.
The March 9 storm had been forecast to drop heavy valley rain and up to 2 feet of snow in upper elevations of the Cascade Range with the possibility of flash floods in the Wenatchee area, Okanogan Valley and Waterville Plateau.
But the storm ran its course, leaving sunshine and fresh snow above 2,000 feet. Winds reaching 128 mph on Mission Ridge south of Wenatchee blew the storm away faster than expected, minimizing rain, snowfall and flooding, Pattee said.
Stevens Pass received 12 inches of new snow overnight, five measurement sites north of Mount Rainier received 12 inches or more and 6,000-foot-elevation Lyman Lake above Lake Chelan received 15 inches, Pattee said.
From 6,000 feet down to 3,500 feet, snowfall ranged from 4 to 6 inches, he said.
Little snow and temperatures 5 to 15 degrees higher than normal in February have left the snowpack about a month ahead of normal in maturity, he said.
Cooler weather the first half of March slowed the melt but a warm second half of March will accelerate it, he said.
The March 12-13 storm dumped 22 inches on Mount Crag in the eastern Olympics, Pattee said.
“That’s almost an inch an hour. It’s high avalanche danger. It was the heaviest in the state. But Stampede Pass (in the central Cascades near Snoqualmie Pass) received no snow, so it was a hit-and-miss storm,” he said.
The Olympics and Mount St. Helens received the most snow, he said.
June Lake at the 3,300-foot level on the south side of Mount St. Helens received 11 inches Saturday and 11 inches Sunday, he said. Bumping Ridge above Bumping Lake in the Yakima Basin received 13 inches of snow and Lyman Lake above Lake Chelan received 7 inches, he said.