Smoke is shrouding large swaths of the West Coast as wildfires continue to ravage the region. Millions of acres have burned across California, Oregon and Washington, where thick plumes are making it difficult to breathe, creating harmful air conditions that may not let up in some areas for days.

Oregon fire crews continued to battle the more than 30 fires raging across the state, where more than 1 million acres have been scorched and, according to Gov. Kate Brown (D), at least 10 people have been killed. More than 3,000 people were staying in shelters run by local counties, Oregon officials said, which are also following protocols to reduce the spread of the novel coronavirus as residents face overlapping crises.

In California, officials say at least 24 people have been killed. Fire crews are still fighting 28 major wildfires in the state, where more than 3.2 million acres have burned and more than 4,200 structures have been destroyed since the middle of August. One death has been reported in the state of Washington, according to the Associated Press.

The U.S. Postal Service announced it is temporarily shuttering post offices in the three states because of high winds and the continued fires.

At a Monday news conference, Brown said she sent a letter to President Trump requesting that he declare a major disaster in the state of Oregon. She also said fire crews expect cooler conditions that may be helpful in coming days.

“We now find ourselves one week into this, and without question our state has been pushed to its limits,” Brown said, adding: “As we look toward the next few days, my firefighting teams tell me they are optimistic that cooler weather coming toward the end of this week will be a tremendous help.”

Red-flag warnings for “critical fire weather” conditions are in effect for parts of interior southern Oregon and Northern California on Monday, and forecasters expected those to continue through at least Tuesday. Gusty southwest winds, particularly in the afternoons, can cause active fires to spread. Hopes of rainfall in the Pacific Northwest are on hold until later this week, when a cold front could produce some light rain and help clear out the smoke.

Air quality in the Pacific Northwest is among the worst in the world. Portland and Seattle claimed top spots for worst air quality and pollution among major cities around the globe. In Multnomah County, Ore., officials tweeted a dire warning: “NO ONE should be outside.”

In southwest Washington and northwest Oregon, dense smoke advisories warn the visibility is less than one mile. Officials warned of hazardous driving conditions, and cautioned those with respiratory illnesses to stay inside to avoid inhaling smoke.

Conditions in Portland and Salem in Oregon were listed as “hazardous,” according to data from state environmental officials. In Seattle, the air quality index topped 200, which is considered “very unhealthy.” Conditions in Sacramento were listed as “unhealthy.”

Air quality alerts are in effect for parts of California because of smoke impacts from the ongoing fires in the central and northern parts of the state. Those are expected to remain in place “until the fires are extinguished,” according to the National Weather Service website.

In Oregon, smoke is not clearing out from valley areas because of a temperature inversion, with warm air sitting atop cool air below. The cool air is more dense and sinks, trapping harmful fire pollutants and lowering visibility significantly. Various smoke and air quality alerts were in effect in Oregon and Washington because of the active blazes there as well.

Incident meteorologist Dan Borsum said during a Sunday news conference on California’s North Complex Fire that it was “exceptionally difficult” to say when air quality in the region will improve.

“Unfortunately, it’s going to take a substantially strong weather system to come through the region to try to move all the smoke,” Borsum said. “At this point in time, in the next 15 days, there is not a weather system of subsequent strength to cause this air to be moved out of the region. Unfortunately, we’re probably looking through the month of September of maintaining close to this air quality.”

Trump, who tweeted for the first time about the fires in the West on Friday, arrived in California for a brief visit to McClellan Park near Sacramento. He was set to be briefed by local and federal officials as he and Democratic presidential nominee Joe Biden deliver competing remarks to address the fires.

In a speech from Delaware, Biden called the “undeniable acceleration of the punishing reality of climate changeone of numerous crises the nation is facing simultaneously.

We have to act as a nation. It shouldn’t be so bad that millions of Americans live in the shadow of an orange sky and are left asking: ‘Is doomsday here?,’ ” Biden said.

The former vice president sought to contrast his environmental agenda with Trump’s, and pointed to the president’s previous threats to slash wildfire aid to California. Referring to Trump’s visit to California, he said: “We know he has no interest in meeting this moment.”

“We know he won’t listen to the experts or treat this disaster with the urgency it demands, as any president should do during a national emergency. He’s already said he wanted to withhold aid to California to punish the people of California because they didn’t vote for him,” Biden said. “This is another crisis. Another crisis he won’t take responsibility for. The West is literally on fire.”

After landing in California, Trump pushed again for better forest management to address the fires, a call he has repeatedly turned to when asked about the blazes in the West.

“Forest management in California is very important and now it extends to Washington and extends also to Oregon,” Trump told reporters. “There has to be good, strong forest management, which I have been talking about for three years.”

Asked whether climate change has had an impact in California, Trump said: “You’ll have to ask the governor that question. I don’t want to step on his toes.”

During a briefing with local and federal fire and emergency officials, the president pushed back when one official pointed to climate change as driving the wildfires.

California Secretary for Natural Resources Wade Crowfoot called on the president to acknowledge that climate change — not just vegetation management — has had an impact on wildfires.

“I think we want to work with you to really recognize the changing climate and what it means to our forests and actually work together with that science,” Crowfoot said. “That science is going to be key, because if we ignore that science and sort of put our head in the sand and think it’s all about vegetation management, we’re not going to succeed together at protecting Californians.”

Trump responded: “It’ll start getting cooler. You just watch.”

When Crowfoot told the president, “I wish science agreed with you,” Trump responded: “Well, I don’t think science knows, actually.”

Sen. Kamala D. Harris (D-Calif.), Biden’s running mate, is also set to travel to her home state to meet this week with emergency personnel.

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