Graupel: A Real Weather Term or Made Up?

By Howard Manges

Graupel: A Real Weather Term or Made Up?

October 23, 2013 Updated Oct 23, 2013 at 10:47 PM EDT

(WBNG Binghamton) WBNG meteorologists often refer to specific types of precipitation in their forecast. One in particular, 'graupel', may leave viewers with questions.

The term seems to confuse more people than not.

Graupel is often misidentified as snow, hail, sleet or sometimes even freezing rain.

It can be correctly referred to as snow pellets.

Hail only occurs during thunderstorms and is most often clear like an ice cube.

Sleet forms when a liquid raindrop freezes into a small chunk of ice before it hits the ground.

Freezing rain is rain that hits the ground as liquid, but contacts a surface that is at or below freezing and immediately freezes into a thin sheen of ice.

So what is graupel? When conditions are right, an ice crystal, or snowflake, can fall through a cloud that contains super-cooled, liquid water droplets.

As the ice crystal collides with super-cooled droplets, these droplets freeze onto it immediately.

This process of collision and growth is called accretion.

The ice crystal continues falling through the cloud and bumps into more and more water droplets.

The accretion process continues until the snowflake begins losing its shape and takes on more of a globular shape.

An easy way to identify graupel is to think of a dish of the tiny ice cream pellets called Dippin’ Dots.

Graupel also sometimes resembles the Styrofoam filling inside a big stuffed bean bag.

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