Wildfire Smoke Plume Over Eastern Idaho

September 09, 2021


Photographer: Glenn McCreery

Summary Author: Glenn McCreery

On June 21, 2021 at approximately 5 PM Mountain Daylight Time (MDT) a wildfire, the “Black Knoll Fire”, started in an unpopulated area approximately four miles northeast on the town of St. Anthony, Idaho. The material burned was mostly grass, sagebrush, and juniper. Organic matter burns at a lower temperature and produces a lighter gray plume than the black, higher temperature, plume from burning oil or a house fire. Such scenes are becoming more common now that wildfire season has become longer and the fires more intense due to climate change.

I photographed the fire at 7:43 PM MDT from Idaho State Highway 33, at a distance of approximately 10 miles to the southeast of the fire. By this time, the fire had grown to about 100 acres (40 hectares). The fire continued to grow to approximately 433 acres (175 hectares) before it was completely contained the next day.  I calculate from the camera image dimensions and focal length (105mm) and approximate distance to the fire, that the plume reached a maximum height above the ground of approximately 1 mile (1.6 km). The angle that the initial plume makes compared with vertical is accounted for by an estimated 7 to 10 mile per hour (11 to 16 kph) wind blowing from the southwest, although there are no nearby weather stations from which to check my estimate.

Photo data: Canon 5D IV camera with Canon 24-105mm L lens at 105mm. ISO 200, f:8.0, 1/1000s. Minor adjustments in Photoshop CC.

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