Hydrometeor
|
Description
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Drizzle
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Liquid water drops less than 0.5
millimeters (0.02 inches) in diameter
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Rain
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Drops with diameters greater than 0.5
millimeters (0.02 inches). Also widely scatter drops of smaller size.
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Freezing Drizzle
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Drizzle that freezes on contact with the
ground
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Freezing Rain
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Rain that freezes on contact with the
ground.
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Snow
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Precipitation in the form of ice crystals.
They can be of various sizes. Snowflakes are aggregates of ice
crystals, often of the dendritic form, and can reaches several inches
in size.
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Snow pellet
or graupel
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White, opaque grains of ice with diameters
between about 2-5 millimeters (0.1 to .2 inches). Can be spherical or
conical. Snow pellets are brittle.
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Snow grain
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Small, white opaque grains of ice. Sizes
are generally less than 1 millimeter (.0.4 inches). The ice equivalent
of drizzle, they are fairly flat or elongated..
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Ice pellet
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Transparent or translucent pellets of ice
that are spherical or irregular in shape, but rarely conical.
Diameters are less than 5 millimeters (0.2 inches). Ice pellets bounce
when the hit ground. Sleet is composed of ice pellets.
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Hail
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Precipitation in the form of pieces of ice
with diameters greater than 5 millimeters (0.2 inches). Hailstones are
either transparent, or have concentric layers of transparent and
opaque ice. Observed during intense thunderstorms.
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