"All Hail Haiku"
You might think that "hail" would be a pretty straightforward word describing frozen hard things dropping from the sky. You’d be wrong. It turns out that there is a variety of frozen hard things dropping from the sky, for example, hailstones, soft hail, sleet, graupel, and snow pellets. Some of these happen in winter, some in summer. Moreover, various cultures regard these phenomena differently. There are even differences between British and American usage. Before looking at the way these basic terms are used in haiku, let’s dwell a moment on definitions.
Hail is the most generic word. Encyclopædia Britannica says “[any] solid precipitation in the form of hard pellets of ice that fall from cumulonimbus clouds is called hail.” Britannica then distinguishes three basic types:
True hailstones—“hard pellets of ice, larger than 5 mm (0.2 inch) in diameter, that may be spherical, spheroidal, conical, discoidal, or irregular in shape and often have a structure of concentric layers of alternately clear and opaque ice.”
Snow pellets or soft hail—“which are white opaque rounded or conical pellets as large as 6 mm (0.2 inch) in diameter. They are composed of small cloud droplets frozen together, have a low density, and are readily crushed.” Soft hail is also called graupel (from the German word Graupel) a term used by meteorologists and increasingly by the English-speaking public.
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