SALEM, Ore. — Amid dry heat and gusty winds, thousands of firefighters made little headway Wednesday containing scores of fires burning across the American West, as forecasts offered only slight hope that conditions would turn more favorable in coming days.

A stiffening overnight wind, sweeping from the north and east, kicked up new fires and blew new life into simmering ones from the Cascade Range in the northwest to the Angeles National Forest east of Los Angeles. Those winds are predicted to spike in Southern California during the next few days, creating fresh concern that blazes in the region could drive toward more populated areas.

The fires have fed on heat and dry conditions, particularly in California, where more than two dozen major fires added Wednesday to the record total acreage burned in the state so far this year. But fires in parts of Washington state, including regions with some of the highest rainfall totals in the nation, served as a bracing reminder that climate and weather are shifting in the West at a now-noticeable rate.

Here in Oregon, where a number of counties have declared emergencies, the Glendower Fire in the state’s south grew through Wednesday and raced through the small cities of Talent and Phoenix, causing what witnesses described as major damage along the way. The flames on Wednesday threatened Medford, a regional economic hub of 82,000 people.

More than 42,000 Oregonians have been ordered to evacuate their homes, a frightening, disruptive annual routine in California but a relative novelty for its northern neighbor. Some of those who fled gathered in an evacuation center on the state fairgrounds here in the capital, describing a rushed, fearful flight under a sky raining ash.

Many of them did not know if they had homes to which they could return.

Leslie Boatman, 39, sat in her car among the RVs and tents of other evacuees with her small dog, Cuddles, and her 66-year-old mother in the passenger seat. The family fled two days earlier from Gates, Ore., a tiny town about 30 miles southeast of Salem.

Her home there was threatened by the Santiam Fire, formerly known as the Beachie Creek Fire, which began in Willamette National Forest last month and has burned more than 132,000 acres.

Boatman was working an overnight shift Monday at a Kroger bakery when the evacuation order was announced for Gates, where she lives with her parents. Her mother, who declined to give her name, just had time to grab shoes, a jacket and the dog.

Fire broke out along the highway as they drove to a Safeway parking lot, where they slept in their cars. On Tuesday morning, Boatman visited Walmart to buy a change of clothes, since she wasn’t able to go home to pack. They arrived at the evacuation site Wednesday morning.

The family has lived in the area for most of their lives and have never faced a wildfire like this one. They have heard through family friends that their entire neighborhood was destroyed.

“I don’t want to believe anything yet,” Boatman’s mother said.

The new round of wildfires started during a record, now-fading heat wave that heightened fire risks across the West, where more than 70 fires are burning in at least a half-dozen states. Fire has charred more than 2.3 million acres in California alone, a record for a state that has endured its deadliest and most far-reaching wildfires in history in just the past three years.

California’s climate has shifted rapidly to one of extremes, where short wet seasons, which feed vegetation across forest floors and in heavily wooded neighborhoods that have allowed home-building for years, are followed by intense heat. The key driver of large fires this year are stiff, moisture-free offshore winds that have come weeks ahead of schedule and are threatening to supercharge fires in Southern California as they strengthen in coming days.

Those winds have severely complicated efforts by the more than 14,000 firefighters struggling against blazes across the state. Known as Diablos, Sundowners and Santa Anas, the gusty winds produce everything from mushroom cloudlike plumes of smoke that reach 40,000 feet in height to vortexes that make it impossible for firefighters to contain an advancing fire.

“I’m kind of at a loss for words right now,” said Neil Lareau, an expert on fire behavior at the University of Nevada at Reno. “I can’t keep up with the number of extremes and unprecedented circumstances that have developed with this.”

Wildfire season is a natural part of many ecosystems, but climate change has these fires burning hotter and longer throughout the year. (John Farrell/The Washington Post)

Climate change, which raises overall temperatures and causes more evaporation from soils and vegetation, is the constant when it comes to this year and other recent harrowing fire years.

“This year fits into a string of years that we’ve seen play out in California and other areas globally whereby warmer and drier fire seasons lead to drier fuels, and that provides a critical ingredient to fire activity,” said John Abatzoglou, an expert on fires and climate at the University of California at Merced. “There’s very little doubt that the card that we’ve drawn in terms of climate set the table in terms of what we’re seeing play out this year. And we’ve seen more and more years like this, partially as a result of ­human-caused climate change.”

In California, strong winds have whipped up the Bear Fire near Oroville, a city north of the state capital of Sacramento. A wind shift drove the flames westward through early Wednesday morning at a stunning rate. The fire’s footprint expanded by about 250,000 acres in just 24 hours.

The region has seen more than its share of fire-caused tragedy in recent years. The Bear Fire is not far from Paradise, the foothill city that burned to the ground two years ago in the deadliest fire in state history. Eighty-five people died in the blaze, many of them overwhelmed in cars and on foot by the wind-driven flames.

Late Wednesday, Butte County law enforcement officials announced that three people had died in the Bear Fire and that 12 were missing.

The wind forecast for Oroville is uncertain, but smoke from the Bear Fire and others in the north left Bay Area residents under a smoke-darkened sky, lit a grim orange by the masked sun, throughout the day.

Farther south, though, Santa Ana winds are expected to strengthen through Friday, causing concern that several fires will change course and head toward major cities.

Among them are the Bobcat Fire, which sparked up Sunday east of Los Angeles in the Angeles National Forest and has burned more than 10,000 acres, and the Valley Fire in eastern San Diego County, which has destroyed a dozen buildings and charred close to 20,000 acres. Neither fire is close to even a quarter contained.

Fires across southwestern Oregon prompted evacuations and emergency responses throughout the state on Sept. 8. (The Washington Post)

In southern Oregon, the Glendower Fire started early Tuesday in Ashland, a college town about 15 miles southeast of Medford that each year holds an acclaimed Shakespeare festival. By dawn on Wednesday, the fire, also known as the Alameda Fire, had reached the outskirts of Medford, according to residents of the city who asked for prayers on social media accounts.

“This could be the greatest loss of human life and property due to wildfire in our state’s history,” Gov. Kate Brown (D) said during a news conference Wednesday.

“These next several days are going to be extremely difficult,” Brown said.

In a news release, the Office of the State Fire Marshal said firefighters and equipment had been mobilized to address the crisis in Medford, as well as in the nearby cities of Phoenix and Talent that witnesses said had already been damaged by fire.

Doug Grafe, chief of fire protection for the state’s Forestry Department, told reporters Wednesday that “we are absolutely in unprecedented times.”

“This is new territory for us,” he said, noting that strong winds are traveling down canyons and driving fires deep into valleys across the state, especially along the western slopes of the Cascades. “Absolutely no area of this state is free from fire.”

In the Salem fairground parking lot, Vivian Hill waited Wednesday outside her car, where a cat and four kittens napped in the driver’s seat. She had fled her home in Lyons, Ore., before dawn on Tuesday, after her phone rang and an automated voice from the county told her to leave.

As she scrambled to do so, two of her other kittens ran away, so she wasn’t able to get them into the car to evacuate. She worried about her beloved cat with a split lip, Willy Wonkers, back in the home she fled.

Wilson reported from Santa Barbara, Calif., and Mooney reported from Washington, D.C. Timothy Bella, Andrew Freedman, Jason Samenow and Kim Bellware in Washington, D.C., contributed to this report.