The growth of ice crystals in a supercooled water cloud

Abstract Equations are derived for the growth rate of ice crystals in the form of thin plates and prismatic columns suspended in a supercooled water cloud of given temperature. The effect of the fall motion of the crystal on its development is discussed ‐ in particular a criterion is derived for the transition from polyhedral to dendritic growth. Ice crystals grown in supercooled water clouds produced in large cold chambers reveal a double change of habit in the temperature range 0°C to −40°C. Experimental determinations of the growth rates of plate crystals growing at −2.5°C and prisms at −5°C are in fairly good agreement with the theory.