Haze from the wildfires in the western United States has reached Indiana, resulting in reduced visibility and some air quality issues.

Andrew White, meteorologist for the National Weather Service in Indianapolis, said it is not dangerous to be outside, but people who are more sensitive to the air quality should avoid exposure if possible.

The haze Wednesday was more intense, White said, with some of the haze coming closer to the surface. The haze will lessen but continue Thursday into Friday, he said.

“We are in the perfect line of the jet stream to move the smoke into Indiana,” White said. “We dealt with this last year in September with a similar situation with a lot of wildfires out west. This year the air is a little closer to the surface.”

The haze is not an issue for air travel, because the smoke is so far from the fire source it is diffused enough not to be an issue for pilots.

For those who have breathing issues, White recommends limiting time outdoors, and delaying outdoor work such as lawn mowing.

Climatologist Greg Bierly in Indiana State University’s Earth and Environmental Systems said the weather patterns for the next few days in Indiana will likely be dry until the weekend.

“There will be a lot of haze and air quality that dominates,” Bierly said, “so we will have days with this haze overspreading. In the Midwest, it’s not severe, but in terms of fine particles, it’s putting us in the orange or unhealthy category. People with underlying respiratory issues and asthma will want to stay inside.”

Wildfires in the American West, including one burning in Oregon that’s currently the largest in the U.S., are creating hazy skies as far away as New York as the massive infernos spew smoke and ash into the air in columns up to 6 miles high.

Strong winds blew smoke east from California, Oregon, Montana and other states. Oregon’s Bootleg Fire grew to 616 square miles — half the size of Rhode Island.

Fires also grew on both sides of California’s Sierra Nevada. In Alpine County, the so-called California Alps, the Tamarack Fire caused evacuations of several communities and grew to 61 square miles with no containment. The Dixie Fire, near the site of 2018’s deadly Paradise Fire, was more than 90 square miles and threatened tiny communities in the Feather River Valley region.

The smoke in the eastern U.S. was reminiscent of last fall when multiple large fires burning in Oregon in the state’s worst fire season in recent memory choked the local skies with pea-soup smoke but also impacted air quality several thousand miles away.

One locally noticeable phenomenon has been the unusual appearance of the sun in the morning and evening, noted meteorologist Jesse Walker of WTWO-TV.

“The particles from the smoke scatters the red and orange wavelengths of the sunset,” Walker explained. “Both sunsets and sunrise have more red and more orange.”

The smokey haze following the jet stream extends from the Rockie Mountains up into southern Canada and swings down to Atlanta and South Carolina.

Walker said an Air Quality Action Day has been declared for Thursday for all of Indiana, and that could continue Friday.

To a degree, Walker said, the haze also kept temperatures from going higher./

But by the weekend an air mass from the south will move in, bringing higher temperatures and possibly rain.

The Oregon fire has ravaged the southern part of the state and has been expanding by up to 4 miles a day, pushed by gusting winds and critically dry weather that’s turned trees and undergrowth into a tinderbox.

Fire crews have had to retreat from the flames for 10 consecutive days as fireballs jump from treetop to treetop, trees explode, embers fly ahead of the fire to start new blazes and, in some cases, the inferno’s heat creates its own weather of shifting winds and dry lightning. Monstrous clouds of smoke and ash have risen up to 6 miles into the sky and are visible for more than 100 air miles.

The fire in the Fremont-Winema National Forest merged with a smaller nearby blaze, and it has repeatedly breached a perimeter of treeless dirt and fire retardant meant to stop its advance.

At least 2,000 homes have been evacuated at some point during the fire and another 5,000 threatened. At least 70 homes and more than 100 outbuildings have gone up in flames. Thick smoke chokes the area where residents and wildlife alike have already been dealing with months of drought and extreme heat. No one is known to have died.

Extremely dry conditions and heat waves tied to climate change have made wildfires harder to fight. Climate change has made the West much warmer and drier in the past 30 years and will continue to make weather more extreme and wildfires more frequent and destructive.