Pyrocumulus Clouds Over Fire in Southwestern Utah
June 28, 2016
Photographer: Ron Smith
Summary Author: Ron Smith
The photo above shows clouds that formed over a wildfire near Pine Valley, Utah, on June 21, 2016. Intense heat from a wildfire can quickly trigger an uplift of air to form a rapidly rising convection cell. As this hot air rises and cools, water vapor condenses around the tiny particles of soot, ash and dust to form a cumulus cloud above the smoke column. Sometimes this pyrocumulus cloud will grow into a cumulonimbus cell. Rain that falls from such a cloud may help contain the fire. On the other hand, if the cumulonimbus formation produces cloud-to-ground lighting, it may trigger other fires. This pyrocumulus cloud above the Pine Valley fire never produced rain. However, because winds were light, firefighters were able to gain control of the blaze within one day.
The stalk in the foreground at lower right is an Ocotillo shrub. This spiny plant is native to lower elevations of the Mojave Desert, along the Colorado River, and much of northern Mexico. Though not indigenous to Utah it does rather well in well-drained sandy soil.
Photo Details: Camera Model: NIKON D5100; Lens: AF-S DX VR Zoom-Nikkor 18-55mm f/3.5-5.6G; Focal Length: 55mm (35mm equivalent: 82mm); Aperture: ƒ/11.0; Exposure Time: 0.0080 s (1/125); ISO equiv: 200; Time: 5:30 PM; Software: QuickTime 7.7.1.