Smoke from the Swan Lake Fire spread across much of Southcentral Alaska, steadily dropping air quality across the region. The effects of the fire could be felt and seen in town soon after the fire began on June 5. The rapid growth of the fire caused air quality to reach levels considered unhealthy for everyone. 

The air quality index in Anchorage climbed to 159 Friday at noon, a level considered unhealthy for everyone and dangerous enough to cause more serious health effects in sensitive groups of people. 

Particulates in the atmosphere from the growing wildfire settled over Anchorage in a thick cloud of smoke early Friday morning to light wind and a dominating ridge of high pressure. 

Air quality is constantly changing. It is affected by everything from smoke to wind and rain, even pollution. In the presence of a wildfire, wind often carries the smoke away from the fire itself — exactly what happened with the Swan Lake Fire. Smoke from the fire traveled some 50 miles to settle in over Anchorage. Light wind and high pressure dominating the region allowed the atmospheric particulates in the smoke to settle from the atmosphere down to the surface overnight. 

Daytime heating will help bring relief from the unhealthy air. As the sun heats the ground, temperature differentials will cause wind to pick up throughout the day. Increased wind will blow some of the smoke out of the Anchorage bowl. This trend is expected in a weather pattern similar to what we are currently seeing. 

Poor air quality in the morning improving through the day as winds move the unhealthy particles from low-lying areas. You can see this in the animation below of air quality Thursday and Friday in Anchorage. 

Unfortunately, there is no immediate change in the forecast. The same warm, dry weather pattern that favors additional fire growth also favors unhealthy air. Without wind or rain, the smoke will settle in areas around the fire up to 100 miles away. That means unhealthy air quality is likely as well as additional growth of the Swan Lake Fire. 

For the latest information on the Swan Lake Fire, follow Swan Lake Fire: 163,714 acres, 37% contained 

For the latest forecast and update on air quality stay with the KTVA weather team and download the KTVA weather app from the App Store or Google Play Store.

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