HAIL is frozen raindrops, though hailstones are frequently much larger than any single raindrop which could be formed by any means. Rising convection currents, consequent on some local instability of the atmosphere, result first in a heavy cloud— usually cumulonimbus in type—and then in raindrops which are carried upwards and freeze in the cooling air; during descent the hailstone receives another coating of water which may be frozen during a subsequent ascent in another part of the storm. This results in a concentric structure, but two or more stones may be cemented together until they assume large proportions and may reach 3 or 4 in. in diameter and a pound or more in weight; such masses of ice are capable of inflicting considerable damage. "Soft hail," Ger. graupel, Fr. gresil, consists of pellets of closely agglom erated ice crystals, and is a form of snow (q.v.) . Soft hail breaks with a splash on impact with a hard substance, and therein differs from true hail; it also occurs with winter or spring storms as compared with the more usual summer thunderstorm with which hail is associated.