5 October 2014

Yesterday afternoon I was caught in a graupel storm.

I was standing on Bellefield Avenue looking at the Cathedral of Learning through binoculars when the clouds darkened, the wind increased and it started to rain.  I was trying to find the peregrines.

The rain turn white and then, between the Cathedral of Learning and Heinz Chapel, it didn’t come down.  It floated up.  What was this?

A woman ran past me talking on her cellphone, “I’ve got to hang up. It’s hailing out here.”

Why was it hailing in 46 degree weather without a thunderstorm?

When I got home I looked up the NOAA weather forecast discussion which said, “Shortwaves combined with cold air aloft will bring scattered showers to the region today.  Some isolated graupel is also possible.”

Graupel is a German word for “precipitation that forms when supercooled droplets of water collect and freeze on a falling snowflake, forming a 2–5 mm ball of rime.”(*)

The balls look like hail but they’re fluffier.  No wonder they were floating on the updraft at the Cathedral of Learning.

It wasn’t hailing. It was graupeling.

(photo of graupel in Elko, Nevada via Wikimedia Commons.  Click on the image to see the original.)

(*) definition from Google.  By the way, “graupel” fails all my spell-checkers so I’m guessing that “graupeling” is spelled with one L as is normal when adding ‘-ing’ to ‘el’ in American English.