A massive fire burning in north-central Washington — the largest in the state's history — is driving heavy smoke into nearby B.C. communities.

Air quality advisories remained in place for much of southern B.C. Monday as forest fires continued to burn across the region.

Okanagan Running Info uploaded this video to Facebook showing the change in air quality between Thursday and Sunday this week at Kelowna's downtown waterfront.

Reduced visibility

B.C. fire information officer Kevin Skrepnek says the heavy blanket of smoke acts like cloud cover by reflecting some of the sun's heat away from the ground and trapping some humidity closer to ground level.

The smoky skies made driving in the Okanagan region a challenge for some as visibility was reduced.

WRB bridge in <a href="https://twitter.com/hashtag/kelowna?src=hash">#kelowna</a>. Smoke from the WA fires affecting visibility. <a href="https://twitter.com/hashtag/bcwildfire?src=hash">#bcwildfire</a> <a href="https://twitter.com/hashtag/okanagonfire?src=hash">#okanagonfire</a> <a href="https://twitter.com/hashtag/airquality?src=hash">#airquality</a> <a href="http://t.co/8FepAIGDPa">pic.twitter.com/8FepAIGDPa</a> —@MsHealthyBriggs

Grand Forks, B.C. resident Karen Bull wears a mask as she works in her garden. (Karen Bull)

Still smokey today in the <a href="https://twitter.com/hashtag/Okanagan?src=hash">#Okanagan</a>, supposed to see the lake and mountains and even Naramata here, but nope, smoke. <a href="http://t.co/ncCmwR4S8J">pic.twitter.com/ncCmwR4S8J</a> —@InfinitumFilms

The smoke in Grand Forks, B.C. made it a challenge to see nearby farms. (Karen Bull)

Kelowna, as seen from Knox Mt. Park, was blanketed in a haze of smoke. (Rodney Saigeon)

Vibrant sunsets

The wildfires have also resulted in fiery sunsets.

.<a href="https://twitter.com/bcalmanac">@bcalmanac</a> listener Mark Windsor sent us this shot of a smoky sunset in Grand Forks, due to Lynch Creek fire <a href="https://twitter.com/hashtag/cbc?src=hash">#cbc</a> <a href="http://t.co/MyuqmSiZA4">pic.twitter.com/MyuqmSiZA4</a> —@bcalmanac

In Grand Forks, where the 227-square-kilometre Kettle Complex wildfires are burning only a few kilometres away, the air quality is more than five times worse than on an average day in Beijing, a city notorious for its smog problems.

A smoky dawn at Oyama Lake near Kelowna, B.C. on Sunday morning. (Chris Walker/CBC)

South of the border

In Washington and Montana, the smoky skies also created vibrant sunsets and eerie photos.

Glacier National Park, in Montana, was also blanketed in smoke.