Last night, we got our first frozen precipitation of the year, and it was graupel. Graupel is caused when a normal snowflake crystal falls through a region of supercooled water droplets: droplets that are way below freezing temperatures, but have remained liquid. If any of the supercooled water touches a snowflake, it instantly freezes onto the snowflake as a little lumpy drop. So as the snowflakes fall, they collect little ice bits until they're tiny round snowballs. It's different from hail - a solid ball of ice - because it's soft and fluffy. Sometimes called "soft hail."
I think I've seen it once before, but it's not terribly common here. On the other hand, cold temperatures aren't common here either; I don't know how common graupel is in regions that get snow more than once or twice a year.
( ten pictures of graupel )
Graupel is a major avalanche cause, because it's basically a layer of ball bearings; they don't lie flat or get hooked on eachother like regular snowflakes. If you get snow on top of the ball bearings, it will very easily slide off down a mountain. Much like our car did this morning. We ... might be stuck here for a bit.
(We're fine, the car is fine, it was a very slow slide, ably controlled by![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png)
juli .)
I think I've seen it once before, but it's not terribly common here. On the other hand, cold temperatures aren't common here either; I don't know how common graupel is in regions that get snow more than once or twice a year.
( ten pictures of graupel )
Graupel is a major avalanche cause, because it's basically a layer of ball bearings; they don't lie flat or get hooked on eachother like regular snowflakes. If you get snow on top of the ball bearings, it will very easily slide off down a mountain. Much like our car did this morning. We ... might be stuck here for a bit.
(We're fine, the car is fine, it was a very slow slide, ably controlled by
juli .)
