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Snow Fog

Noticed snow fog in parts of Johnson County on the way to work this morning. It was rising through the trees in some of the valleys, and then re-freezing on the branches making some beautiful, glass-like formations on every twig. Wish I could have stopped to get some photos, but as usual I was in a big hurry. Anyone know what conditions it takes to make this stuff? - Tried finding something about it online but couldn't locate anything. Really beautiful!
 
Hoar frost? I've seen it many times, and it is indeed quite awesome. It sounds like, for whatever, some of the snow is melting and evaporating (or just sublimating perhaps) quick enough to saturate the air nearby and create some freezing fog. Since temps are below freezing, things such as branches can become ice-covered, creating some awesome photo opps. Hoar frost tends to have a crystal-like appearance, while rime icing tends to be a glass-like coating. Rime icing, in my experience, tends to be more common in a freezing-drizzle or freezing rain situation, when there's a lot of moisture in the air without a whole lot of time for crystallization.
 
Hoar frost ... yeah ... I'm going to look that up. Found this pic on Roger Edwards' site: http://www.stormeyes.org/tornado/SkyPix/pumpjack.htm

The interesting thing this morning was that it was rising in several 'pockets' through the trees, making it almost look like steam vents in the snow.

I hate working when there are some magical things to take pictures of outside while I'm stuck behind a desk.
 
If there was fog present than technically it was rime ice. Rime is just frozen cloud droplets. When I worked at the Mount Washington Observatory anytime it was below freezing and we were in the fog we got rime ice. We had optimal conditions up there, so it grew rapidly and often to great lengths. I have seen rime in the valleys during very cold, foggy mornings.

Maybe somebody knows the official definition, but hoar frost is different. Hoar frost forms on the ground or within the snow pack, and fog is not required.

Jeff...rime is not associated with freezing rain/drizzle. Officially that is called glaze ice. Glaze is more like water ice, rime and hoar are feathery and crystal like.

Here are some photos I took at Mount Washington.

Lots of rime.
kmwn0008.jpg


More rime on the instruments.
kmwn0013.jpg


Rimed over icicles.
kmwn0018.jpg


Thick glaze with a hint of rime.
kmwn0004.jpg
 
It's cool to see how the ice crystal formations are shaped by the wind under those gale-force conditions Mt. Washington is under so frequently ... looks like something out of a movie.

I had some friends who actually camped on Mt. Washington in winter one time - and though they were experienced hikers and had all the right gear, it still ended up being more than they bargained for. They pretty much thought they were going to die. Beautiful place, though -
 
Maybe there is some lava near the surface around St. Joe. Uh oh!
 
Maybe there is some lava near the surface around St. Joe. Uh oh!

Yeah ... maybe Johnson County is the next Yellowstone Park ... that's exactly what it reminded me of. Maybe that's why Brush Creek has been boiling lately ... until now I just thought it had to do with all the chemical spills.
 
If there was fog present than technically it was rime ice. Rime is just frozen cloud droplets. When I worked at the Mount Washington Observatory anytime it was below freezing and we were in the fog we got rime ice. We had optimal conditions up there, so it grew rapidly and often to great lengths. I have seen rime in the valleys during very cold, foggy mornings.

Maybe somebody knows the official definition, but hoar frost is different. Hoar frost forms on the ground or within the snow pack, and fog is not required.

Jeff...rime is not associated with freezing rain/drizzle. Officially that is called glaze ice. Glaze is more like water ice, rime and hoar are feathery and crystal like.

Here are some photos I took at Mount Washington.

Lots of rime.
kmwn0008.jpg


More rime on the instruments.
kmwn0013.jpg


Rimed over icicles.
kmwn0018.jpg


Thick glaze with a hint of rime.
kmwn0004.jpg

Good posting.

Only some additions from me:
- rime needs wind to form and to grow
- rime is like a rough and coarse crust
- hoar frost is fine and mostly thin
- rime ice/hoar frost has little less albedo than snow!

I've also made lots of rime pictures, mostly from the Brocken in Central Germany. This mountain is a little bit comparable to the Mt. Washington and also famous for windy, cloudy and foggy climate.

Some pictures and snapshots:

001.jpg

("no winter service")

growing to...

012.jpg




rime on trees:

starting...
003.jpg


growing to...


010.jpg


012.jpg


One of my latest pictures:

dreamland4.jpg


I love it and I can show lots of impressive photos ;-)

Bye
Chris
 
I'm not sure it does need wind to grow. It just grows more quickly with wind. During optimal conditions, high 20's and lots of wind, rime can grow over 1 foot per hour. Rime always grows into the wind.

But, on calm and cold mornings rime will grow without wind. When this happens it covers all surfaces, opposed to those facing into the wind.
 
Not even a week or so after I got my Nikon D70 last January (10th-11th) we had an incredible rime icing event in Dodge City...after 2 solid days of freezing fog. Here are a couple of shots from that event around Dodge.. a persistent northeast wind allowed the 2" buildup on north facing exposed surfaces:

<img src=http://photos.photosig.com/photos/63/81/1438163-0663c49b97dcabea.jpg>

<img src=http://photos.photosig.com/photos/39/63/1436339-6aaf883122ec38a8.jpg>

<img src=http://photos.photosig.com/photos/51/14/1431451-84bb347c429ea80c.jpg>

Mike U
 
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