Graupel

weather · snow · ice crystals

What is graupel?. Graupel is precipitation made of small, round balls of ice that are 2 to 5 millimeters across. It forms when supercooled water droplets (droplets colder than freezing) in the air stick and freeze onto falling snowflakes.

Popcorn snow texture. Graupel feels crispy and crunchy because each little ball has a bumpy, opaque coating of frozen rime on the outside. This coating is what makes it look and feel different from regular snow or ice pellets.

How it forms. As snowflakes fall through clouds filled with supercooled water droplets, those droplets collect and immediately freeze onto the snowflake's surface. Layer by layer, the frozen droplets build up until the snowflake becomes a tiny, bumpy ice ball.

Many names, one thing. Graupel has lots of nicknames including soft hail, hominy snow, granular snow, snow pellets, and popcorn snow. People around the world use different names for this same type of precipitation.