Fire Cloud with a Pileus on the top

Picture of the Day for September 29, 2026

Researchers recorded unusual observations of an ephemeral pileus cloud hovering over a smoke-infused cloud that increased above a wildfire in Montana.

Sep 29, 2026

In summer season 2026, researchers took off to obstruct and study the towering, smoke-infused clouds that wildland fires often develop. Throughout an August 11 flight over the Sand Creek fire in Montana, they returned with a reward– observations of an ephemeral pileus cloud hovering atop among the imposing fire clouds.

Smooth, veil-like pileus clouds are widely known to climatic researchers and cloud enthusiasts and considered indications of particularly energetic convectionScientists seldom observe a pileus cloud engaging with a fire cloud– understood as a pyrocumulus (pyroCu)– in as much information as they did on this flight, part of NASA’s INSPYRE (Injected Smoke and Pyrocumulonimbus Experiment) project.

Called after the Latin for “cap,” pileus clouds usually form when increasing columns of air hit an adequately damp layer of air up. Over the Sand Creek fire, a fast-rising updraft warmed by the fire displaced air vertically and required a horizontal layer of moister air sitting above it up. The procedure resembles how air required over a mountain can produce clouds, discussed Neil Lareau, INSPYRE’s deputy job private investigator. “But in this case, the pyrocumulus itself was the ‘mountain,'” he stated. As the displaced air was pressed up, it cooled, and its water vapor condensed into a pileus cloud.

The set of images above was caught at 5:40 p.m. regional time (23:40 UTC) by the MASTER (MODIS/ASTER Airborne Simulator) on among NASA’s ER-2s, a kind of high-flying research study airplane. The natural-color image left wing reveals the thin, circular pileus atop the turret of smoke and water increasing from the dispersing wildfire. The image on the right reveals the very same minute however consists of shortwave-infrared (SWIR) observations, which expose the scorched location and actively burning areas along the fire’s boundary.

Pileus clouds are normally rather brief, typically continuing for just a couple of minutes before being surpassed by the underlying convection. Throughout this flight, the researchers gathered MASTER images of the plume approximately every 30 minutes, and the pileus was plainly noticeable in simply one scene. The existence of the cloud mean what Lareau referred to as the “extreme updraft dynamics” within the fire plume and pyrocumulus. At the time of the image, he discussed, the fire was making a quick run up the western side of Mount Comet as winds lined up with the drain channels leading up the mountain.

“The whole scene is amazing,” he stated, keeping in mind that the science group was lucky that MASTER’s noticeable channels recorded the quickly establishing pyrocumulus and pileus cloud, its infrared channels caught the fire’s severe surface area habits, and downward-pointing radars on the plane studied the cloud structure. “This scene is in many ways the core of what we’re after with INSPYRE,” he stated. “We were able to connect and map the surface fire dynamics to the convective plume to the cloud processes.” The image above reveals the cloud in 4 of the 50 channelsor bands, determined by MASTER. The false-color panel on the far right of the image is a mix of shortwave-infrared and noticeable observations, comparable to the best image at the top of the page.

Fires are simply one chauffeur of convection that can produce pileus clouds. Energetic updrafts connected with serious thunderstorms can likewise produce these wispy clouds. Scientists who took part in NASA’s CRYSTAL-FACE (Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment) in Honduras in 2002 reported the existence of thin cirrus clouds in the tropopause above thunderstorms that were most likely the items of pileus clouds.

Volcanic eruptions can produce pileus clouds. Among the more spectacular images recorded by astronauts and released by NASA Earth Observatory is this picture of a pileus cloud masking the top of a volcanic plume increasing from the Sarychev volcano after an eruption in 2009.

MASTER images by RoseAnne Dominguez (Airborne Sensor Facility), annotated by Michala Garrison. Story by Adam Voiland.

• Cloud Appreciation Society, PileusAccessed September 28, 2026.
• EarthSky (2026, April 22) A pileus cloud indicates bad weather condition is on the methodAccessed September 28, 2026.
• Garrett, T.J., et al.[19459086](2006)Convective development of pileus cloud near the tropopause Climatic Chemistry & & Physics, 6( 5 ), 1185– 1200.
• Lareau, N., by means of X (2026, August 13) Here is the matching noticeable images, which reveals the #pyrocumulus cloud in beautiful informationAccessed September 28, 2026.
• NASA Earth Observatory (2026, August 17) Chasing Fire Clouds in Utah. Accessed September 28, 2026.
• NASA Earth Observatory (2016, December 20) A Celebration of Clouds from Space. Accessed September 28, 2026.
• NASA’s Earth Science Project Office, INjected Smoke and PYRocumulonimbus ExperimentAccessed September 28, 2026.
• NASA, INSPYRE. Accessed September 28, 2026.
• NASA, MASTERAccessed September 28, 2026.

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