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Why Southern Arizona skies are so smoky

For those of us who live in the Sonoran Desert, we’re used to seeing cobalt blue skies. Lately, our skies have taken on more of an amber hue thanks to lots of smoke in our atmosphere. So, where’s all the smoke coming from?
Posted at 5:46 AM, Aug 25, 2020
and last updated 2020-09-21 16:52:08-04

TUCSON, Ariz. — For those of us who live in the Sonoran Desert, we’re used to seeing cobalt blue skies. Lately, our skies have taken on more of an amber hue thanks to lots of smoke in our atmosphere. So, where’s all the smoke coming from?

Most of us have heard about all of the wildfires across the western United States including Colorado and New Mexico. The smoke we’re seeing throughout southern Arizona is coming mostly from the wildfires in Colorado and New Mexico. This is because of the position of a strong ridge of high pressure sitting over the Four Corners region.

Air around a high pressure system rotates clockwise. So, when located over the Four Corners, the air from Colorado and New Mexico is pulled right over southern Arizona. Wildfire smoke rises, gets caught in the prevailing winds aloft and the result is smoky skies for us!

Our visibility is even more obscured because we have more moisture in our atmosphere right now. Water vapor gives the sky a hazy look and it gets even worse when smoke is added to the mix. Water droplets act as a great surface for smoke particulates to attach to and, together, water vapor plus smoke can really cause visibility to be reduced.

Air quality can suffer when we get lots of smoke combined with ground-level ozone created by sunlight and heat interacting with pollutants emitted by vehicle exhaust. Sometimes, as has been the case lately, the Pima County Department of Environmental Quality (PDEQ) will issue an Air Quality Health Watch when ground-level ozone levels reach a point that exceed safe levels according to federal health standards. When an Air Quality Health Watch is issued, people who are sensitive to air pollution should try to stay inside and avoid strenuous physical activity.

Unfortunately, it doesn’t look like this pattern will change anytime soon. High pressure will be stubborn to move and no significant rain is forecast to fall over western wildfire areas. The fires will keep burning, the smoke will keep rising and the skies over southern Arizona will continue to take on a hue of amber. Eventually, the pattern will shift and our beautiful cobalt blue skies will return to the desert. Until then, we can enjoy the spectacular red-orange sunsets that result from the smoke and haze in our atmosphere!