07 February 2010


Even if you're not around here (Washington DC area), I gather several folks have heard about our weather.  Having been reminded by JG that not everybody has seen snow, I caught some video of the flakes in action.  And being reminded of Nakaya's work on ice crystal types, I have a still that attempts to catch a few snow crystals.

Snow crystals on my coat sleeve:
Be sure to click on that to see full size.  One thing to notice, aside from the fact that many have already melted, is that most are little needles.  Some of the needles have clumped together, like the one near the loose thread in the middle of the photo.  If you look carefully, you can see that the needles have little balls on their ends. The little balls are liquid water cloud droplets that froze instantly onto the needles as the needles fell through the cloud.  It's called riming, even as it happens to a single snow crystal. (Riming is a serious hazard for aircraft taking off or landing in near-freezing conditions.)

Morning snow (small snowflakes):

Afternoon snow (bigger snowflakes):



Deech56 said...

So after spending two days shoveling snow here in Frederick, MD, I check on my go-to blog and find - - - snow.

But seriously, thanks for the videos; I was noticing the different flakes as they were falling. Growing up in Buffalo gave me a fine appreciation of the different types of snowfalls.

jg said...

Thanks for the snow images. I was watching rain again this weekend, and I was suprised by how many of the fine mist droplets were going upward. For obvious reasons, I did not try to capture it with my video camera.

Deech56 said...

Interesting - this afternoon's snow had the classic flat flakes singly and in clusters. Tonight's snow is more granular. Offices closed again tomorrow, so more snow-watching ahead (along with getting to the work I took/sent home).

jg said...

I have almost a snow story. Where I live we may get hail once or twice a year. Yesterday, I was starting an after school astronomy presentation for a middle school astronomy club and it started to hail. Pow! The students bolted from their seats and ran outside. I would have dismissed them, but before I could be so magnanimous, they were outside running, stomping, and gathering what they could. I encourage Bob to continue this and related precipitation topics.

Robert Grumbine said...

You understand why snow might have been a little on my mind :-) As a Buffalo person, you've probably seen something I always was amused by -- lake effect snowfall with no clouds in the sky. Always very powdery snow and usually a nice sun halo.

I've kind of burned out on snow observing, so haven't been out to see what the flakes are like this time. With the 15-25 m/s (30-50 mph) wind gusts, it's pretty hard to see snowflakes individually anyhow.

You can do your mist videos the way I did the snow videos -- sit inside warm and dry and film through the kitchen window. I concede that this might lack something for precision or authenticity, but it's a lot safer for the camera.

Hail is interesting stuff. I'll make a note about putting together a post about it. Probably closer to my own hail season -- April or so. First day I was delivering newspapers we had a hailstorm.