There’s a decent chance that you have seen precipitation fall and think it’s sleet, or even small hail, when in fact what you are seeing is graupel.

Graupel falls as tiny, soft pellets that are sometimes referred to as “soft hail.” Graupel forms when snowflakes fall through supercooled water droplets, tiny liquid droplets in the atmosphere that are colder than freezing but haven’t yet turned to ice.

When those droplets touch a snowflake, they instantly freeze onto it, coating the flake in a thin, icy shell.

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The result is a small, round and soft piece of ice, typically about the size of a pea, that looks a bit like Styrofoam. Unlike hail, graupel is not solid all the way through and usually crushes easily between your fingers.

It tends to fall during colder weather patterns when there’s enough instability or lift in the atmosphere for those supercooled droplets to form. Graupel can be a sign of convective snow showers or an approaching wintry mix, and while it’s generally harmless, it can make roads and sidewalks slick very quickly.

Jennifer Gray is a weather and climate writer for weather.com. She has been covering some of the world's biggest weather and climate stories for the last two decades.