Definition: Ice pellets: Precipitation of transparent ice particles that falls from a cloud. These particles are usually spheroidal or irregular, and rarely conical. Their diameter is less than 5 mm.
Ice pellets originate as raindrops or snowflakes (less common) that generally fall from Altostratus or Nimbostratus. They fall into a subcloud layer of warm air where the snowflakes melt or partially melt, and then fall into a cold layer of air (below 0 °C) where they freeze and reach the ground as frozen precipitation.
Ice pellets of the form of frozen raindrops are transparent, the less common refrozen snowflakes are, in parts, transparent and, in parts, opaque, depending on whether the snowflake melted or only partially melted.
Ice pellets are not easily crushable. When they fall on hard ground, they generally bounce with an audible sound on impact.
Ice pellets may be partly liquid. Their density is usually close to, or above, that of ice (0.92 g/cm3).