Graupel splatters when it impacts onto a surface. Derived from the German word for barley , graupel is created when supercooled water droplets coat a snowflake with ice or when a supercooled drop develops an outer coating of ice without freezing through. Because graupel forms in convective updrafts and may be pushed quickly downward in descending currents, it may fall when the surface temperatures are significantly above freezing. Snow Grains are white opaque particles, either flat or elongated, and less than 1 mm in length, the solid equivalent of drizzle. Smaller and flatter than snow pellets, they generally fall from stratus clouds rather than in convective clouds.
Sleet is a term for cold weather precipitation that has a few different meanings.
In the US, it refers to ice pellets, but is sometimes erroneously used to mean freezing rain. In UK, sleet refers to mixed rain and snow or melting snow. Our final forms of hard rain are rime and glaze . Hard rime and glaze are more technical subcategories of freezing rain or drizzle. Both are formed by supercooled drops which freeze on contact with a cold surface.