NASA Scientists Capture Rare Pileus Cloud Over Montana Wildfire

Scientists have made rare observations of a pileus cloud forming above a smoke-filled cloud rising from a wildfire in Montana. A pileus is a brief, cap-like cloud that appears when a rising air mass pushes through a layer of moist air above it. The phenomenon is considered ephemeral, meaning it lasts only a short time before dissipating. The event was documented over an active wildfire, with smoke from the blaze contributing to the unusual atmospheric conditions that produced the rare formation.