The Seattle skyline is tough to make out in this view from Gas Works Park, looking south across Lake Union on Friday./ (GeekWire Photo / Taylor Soper)

Stay inside, Seattleites.

That’s been the advice from weather experts this week as historic wildfires spread up and down the west coast, causing smoke to fill the sky. Air quality in the Seattle region is expected to worsen Friday morning, with winds pushing smoke north from fires in Oregon and California. Smoke is expected to slowly decrease on Sunday. 

Update, Sept. 11: Air quality will “continue to worsen” Saturday, according to state officials. Here’s what the smoke radar looks like.

Update, Sept. 12: Little change is expected in the smoke forecast for Saturday. Air quality through Saturday will be at least ‘Unhealthy’ across Western Washington, according to the National Weather Service. The Washington Department of Ecology says the silver lining is that “this is as bad as it should get,” with clearing starting Sunday.

Update, Sept. 13: Via the National Weather Service: “Not much improvement in the smoke today.” But a weather system approaching should help clear the air.

Cities across Oregon and Northern California were hit the hardest this week, with thousands of people forced to evacuate and some deaths reported. “We have never seen this amount of uncontained fire across our state,” Oregon Gov. Kate Brown said.

So what’s going on? And why are the wildfires getting worse?

Scientists pin the cause of the record-breaking California wildfires, which have burned through more than 2.3 million acres, on a combination of climate change, lightning strikes, man-made ignitions, and the fact that people live close to the flames, the Associated Press reported.

Washington Gov. Jay Inslee this week called it a “new world in forest and grassland fires” and said the conditions are so dry and hot “because the climate has changed,” the Tacoma News Tribune reported.

“They are climate fires,” Inslee said on Wednesday. “They are climate fires because that’s what creates the conditions that makes them so explosive.”

Brown added: “Unfortunately, it is the bellwether of the future. We are seeing the devastating effects of climate change in Oregon, on the entire West Coast, and throughout the world.

The Wall Street Journal last week highlighted the “science of wildfires,” noting that fires are getting bigger, more intense, and harder to put out in recent years, in part due to overgrown forests. Century-old policies that force the immediate extinguishing of wildfires instead of allowing them to burn have increased the amount of “ladder fuel,” or small and medium trees that can make fires more dangerous.

Doug Morton, chief of the Biospheric Sciences Laboratory at NASA, told the WSJ that researchers are working on algorithms that can improve forecasting to better anticipate where and when fires are more likely to spark.

Paul Hessburg, a research ecologist based in Wenatchee, Wash., gave a Ted Talk in 2017 about preventing wildfires. He also pointed out the problem of overgrown forests, calling it an “epidemic of trees.”

“After a century without fire, dead branches and downed trees on the forest floor are at powder keg levels,” he said. “What’s more, our summers are getting hotter, they’re getting drier, and they’re getting windier.”

Hessburg recommended using prescribed burning to intentionally thin out trees and burn dead fuels, as well as mechanical thinning and managed wildfires. He encouraged people to voice their concerns to lawmakers to help change policies that make these strategies a reality.

“Until we, the owners of public lands, make it our high priority to do something about the current situation, we’re going to experience continued losses to megafires,” Hessburg said.

As for advice on staying safe, Ranil Dhammapala, an atmospheric scientist with the Washington State Department of Ecology, said a “combination of N95 masks, HEPA filters, air purifiers and clean air rooms is probably what will work best.” Dhammapala responded to questions on the Washington Smoke blog, which has an air quality map for current conditions. The Puget Sound Clean Air Agency also has an air quality guide here.

Here’s how to make your own box fan filter:

Other tips from the Washington Smoke blog include reducing outdoor physical activity and closing windows — though it noted that “ventilation is good for helping prevent COVID-19, so when air quality is good, open them to get fresh air and reduce potential viral load.”

The Washington State Department of Health has an FAQ page to answer questions about COVID-19 and wildfire smoke.

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