Power production resumes at Skagit dams near Sourdough Fire

Seattle City Light has resumed power generation at two dams on the Skagit River as the Sourdough Fire continues to burn in Washington’s North Cascades.

The flames had come close enough to Diablo and Ross dams — and the transmission lines that connect them to Seattle electricity users — that Seattle’s power utility evacuated workers and took the dams offline on Aug. 2.

In an email, Seattle City Light spokesperson Jenn Strang said the utility restored normal operations at Diablo Dam on Tuesday and Ross Dam on Wednesday. Gorge Dam, 4 miles downstream of Diablo, was not affected.

The three dams provide up to a third of Seattle’s electricity.

“At this point, we are completely up and running for what’s normally charged from Seattle City Light. All the power’s been restored and infrastructure’s getting back to normal,” Northwest Interagency Incident Management Team section chief Dean Lange said Thursday at a briefing in Newhalem on firefighting operations.

Strang said Seattle City Light is prepared to turn the power from the dams off again, should the fire jump the protective measures put in place around the dams and their transmission lines.

As of Friday morning, the Sourdough Fire had burned an estimated 1,809 acres, with only 5% of its perimeter contained by fire breaks or other barriers.

As of Friday afternoon, one major bit of infrastructure remained out of operation: Transportation officials closed Highway 20, the North Cascades Highway, a second time Thursday evening.

The route across the North Cascades is closed until further notice.

“It’s closed because we have a lot of rolling debris,” Lange said at a briefing on Friday. “Between the rocks and the trees and the fire, it’s just the right thing to do to close that road down.”

Much of the northern half of North Cascades National Park is also closed to visitors. In addition to areas shut down by the ongoing Sourdough Fire, many wilderness trails and campsites north of Highway 20 are still off-limits after wildfires tore through that part of the park in 2022.

Burned-over areas can remain hazardous for years after a fire, according to the National Park Service, due to falling dead trees, burned stump holes and root chambers, and rolling or flowing, muddy debris.

Cool, humid weather in the North Cascades tempered the Sourdough Fire’s growth this week.

Forecasters expect a heat wave to hit eastern and southwestern Washington starting Sunday.

The National Weather Service predicts the Diablo Dam area will hit 90 degrees Monday through Wednesday.