In a static supercooled cloud dendrites hardly grow at about -15°C except at the pointed tip of a needle-like ice crystal or an isolated thin plate-like ice crystal. When ice crystals are moved slowly in a static supercooled cloud, dendrites grow at about -15° C and the α-axis growth rate increases as the velocity of the dendrites increases; at velocities higher than 20 cm/s, however, the a-axis growth rate decreases as the velocity increases due to the influence of heavy riming. The maximum a-axis growth rate in a supercooled cloud is observed at about -15°C in experiments growing ice crystals in free fall.