What is Graupel?
I never thought that on May 14th, I'd have to search for my ice scraper to clear my car windows before work, but that's what I had to do today. The weather has been a little strange- a few really nice warm days and then WHAM, the freezing cold is back with a vengeance.
I had to stop at the Binghamton Post Office yesterday and when I came out, tiny pellets of snow was falling from the sky. A lady in the parking lot commented that it was "graupel." I had no idea what she was talking about. I know what snow, sleet and hail are, but had never heard the term "graupel." So what exactly is it?
According to Wise Geek:
While graupel has the appearance of white snow pellets, its formation is closer to that of hailstones. Winter storm clouds often contain water droplets which have cooled far below 32 degrees without turning to ice. Sometimes those supercooled droplets contact dust particles or ice crystals and form solid hail. Other times, the supercooled droplets attach themselves to snowflakes and freeze instantly. The air currents within the storm clouds continue to push the ice-covered snow flakes through supercooled water until they become too heavy and fall to the ground as graupel. Because graupel is white and powdery, many people consider it to be a form of snow. Others argue that its formation is similar to hail, so graupel should be considered a form of soft hail. Although graupel typically falls during cold winter storms, it has been known to form along with icy hail during severe thunderstorms and tornadoes. The air temperature near the ground is not as critical for graupel formation as the conditions thousands of feet in the air.
So in a nutshell, graupel is part snow, part hail. And now you know.