NASA researchers capture rare pileus cloud atop a Montana wildfire plume
During an August 11, 2026, flight over Montana's Sand Creek fire, NASA scientists observed a short-lived pileus cloud resting on a pyrocumulus cloud. The event was captured by the MASTER instrument on an ER-2 research aircraft during the INSPYRE atmospheric study campaign.
The pileus cloud, which means "cap" in Latin, formed when a powerful updraft from the wildfire pushed a moist layer of air upward, causing water vapor to condense. According to NASA, this process occurred as the fire moved rapidly up the western side of Mount Comet. The researchers, part of the INSPYRE experiment, used the MASTER sensor to capture both natural-color and shortwave-infrared imagery of the event at 5:40 p.m. local time.
While pileus clouds are known indicators of vigorous convection, observing them interacting with a pyrocumulus cloud in such detail is rare. Neil Lareau, the deputy project investigator for INSPYRE, noted that the imagery allowed the team to link surface fire dynamics to cloud processes. The transient cloud was only visible in one of the 30-minute interval images captured during the flight.
Source: Fire Cloud with a Pileus on Top
