Saturday 24th May 2025

When high-altitude winds encounter the atmospheric obstacle of a large convection cloud, such as the building Cumulus congestus cloud shown here, the winds can be made to rise to pass over it. Any moisture in the airstream can cool as it does so and condense to form a pileus – an accessory cloud resembling a silky smooth sweep of hair. ‘Such drama!’ exclaimed Denise Waterbury (Member 56,618) as she saw a pileus form on a towering Cumulus congestus cloud over Buttermilk Country, Bishop, California, US. She likened it to ‘a goddess in the clouds, with long hair sweeping behind her’.




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