ANN's Daily Aero-Term (07.07.13): Altocumulus Castellanus Altocumulus Castellanus A middle cloud with vertical development that forms from altocumulus clouds. It is composed primarily of ice crystals in its higher portions and characterized by its turrets, protuberances, or crenelated tops. Its formation indicates instability and turbulence at the altitudes of occurrence.
July 7, 2013 - The Aero-News Network