Rime Ice / Freezing Fog at the Lake

[CanisLupusArctos]

This morning brought a phenomenon normally seen only above treeline in the White Mountains and in similar places but it has been known to occur on the lake: Rime ice. This is what happens you have freezing fog. Yesterday evening, temperatures fell rapidly once the sky cleared out. The air quickly reached its moisture saturation point (dewpoint) at 7 degrees (cold air can't hold as much moisture as warm air) and dense fog formed. A breeze from the southeast at 2 mph made the fog move just enough so it froze to everything it hit.

I spent the night out on the lake with a couple of friends in a quincy (a type of igloo) we built. Yes, we are in our late 20s and early 30s but we are male. Around midnight we noticed the handles on our snow shovels were covered in a half-inch of rime ice whose feathers were pointing mostly to the southeast. In the beams of our LED head-lamps we could see the fog was not water droplets but crystallizing into snowflakes around us.

We awoke to find snow falling but the sky had many patches of blue overhead. Around us, and into the distance, we could see that the cloud producing the snow was actually lake fog with a cloud top at about 1,500 feet. Under the clear sky, the day's heat had spent the night escaping skyward. The resulting cold air pooled into the lake because it's a valley among hills, and cold air likes to sink. It's heavy.

The surrounding area, even the air above us, had not cooled enough to reach saturation point (dewpoint.) But the cold air had pooled on the lake surface, where the temperature continued cooling after reaching its dewpoint. Whenever that happens, the excess moisture is forced to fall (precipitate) out of the air. Usually this only happens in clouds above our heads, but this time it happened right at the ground level. We got a tenth of an inch (0.1") snow accumulation from it. The trees on the shorelines were beautiful and frosty covered with the rime feathers this morning.

[Merrymeeting]

CLA, as always, thank you for the very educational and well written post. Something I'd love to see someday but your explaination makes it easy to visualize.

On a related topic, dead of winter with some of the coldest temps seen this year. You're sleeping on the ice in a home-made igloo with 2 other guys. I think I have some advice for why it may be difficult to attract those female wolves to the den :emb:

[tpabrad]

That is awesome, thanks for the great explanation.

[CanisLupusArctos]

On a related topic, dead of winter with some of the coldest temps seen this year. You're sleeping on the ice in a home-made igloo with 2 other guys. I think I have some advice for why it may be difficult to attract those female wolves to the den :emb:

They left me no choice! :laugh:

Here's the kicker... One of the other 2 guys has a girlfriend most men would agree is about a "9.5" (who also can't get enough of fishing!) who watched us all weekend on the WeatherCam and occasionally called his cell phone. As I inferred from their conversations, she was glad to watch and see her alpha male being male with his pack! So... maybe she has a like-minded, like-looking pack of her own...

[Blue Thunder]

this morning brought a phenomenon normally seen only above treeline in the white mountains and in similar places but it has been known to occur on the lake: Rime ice. This is what happens you have freezing fog. Yesterday evening, temperatures fell rapidly once the sky cleared out. The air quickly reached its moisture saturation point (dewpoint) at 7 degrees (cold air can't hold as much moisture as warm air) and dense fog formed. A breeze from the southeast at 2 mph made the fog move just enough so it froze to everything it hit.

I spent the night out on the lake with a couple of friends in a quincy (a type of igloo) we built. Yes, we are in our late 20s and early 30s but we are male. Around midnight we noticed the handles on our snow shovels were covered in a half-inch of rime ice whose feathers were pointing mostly to the southeast. In the beams of our led head-lamps we could see the fog was not water droplets but crystallizing into snowflakes around us.

We awoke to find snow falling but the sky had many patches of blue overhead. Around us, and into the distance, we could see that the cloud producing the snow was actually lake fog with a cloud top at about 1,500 feet. Under the clear sky, the day's heat had spent the night escaping skyward. The resulting cold air pooled into the lake because it's a valley among hills, and cold air likes to sink. It's heavy.

The surrounding area, even the air above us, had not cooled enough to reach saturation point (dewpoint.) but the cold air had pooled on the lake surface, where the temperature continued cooling after reaching its dewpoint. Whenever that happens, the excess moisture is forced to fall (precipitate) out of the air. Usually this only happens in clouds above our heads, but this time it happened right at the ground level. We got a tenth of an inch (0.1") snow accumulation from it. The trees on the shorelines were beautiful and frosty covered with the rime feathers this morning.

Absolutely fascinating, thanks!!

BT

[upthesaukee]

I spent 54 months at Eielson AFB outside Fairbanks Alaska and in the wintertime, we would have the phenomona of ice fog regularly occur.

At temps of about -20 or colder, the moisture in the air would freeze, and create "fog" which was actually tiny ice crystals suspended in the air. It was helped along by emissions from heat sources such as autos, furnaces and the base power plant.

Our control tower was about 110 feet above the ground, and we could see Mt. McKinley 160 miles away, but the runway visibility could be reduced to less than 1/4 mile. If we were above minimums, aircraft would take off, we would not see them until the cleared the top of the ice fog bank where they looked like a fish suddenly jumping out of the water (fortunately staying up :)).

Ice fog would deposit a coating of ice on everything. Telephone wires looked like they were two or more inches thick, cars would have a coating of ice on them, and even the road would have a new coating. The good news as far as the roads were concerned was that while it made for a deeper depth of snow and/or ice on the road, it was so cold that the water content remained frozen, and traction was actually pretty good. Just don't slam on the brakes.

Any outdoor activity during this phenomena would deposit a thin layer of ice on your outer layer of clothing.

You could create your own little cloud of ice fog by taking a cup of hot water and throwing it up into the air, where it would literally instantly freeze, not in one big lump, but as a cloud of water droplets. Neat thing to see.

In my 54 months in Alaska, not once did I sleep in an igloo with 2 other guys, but once I did... oh well, that's another story and I don't want to hijack a thread.:D

[CanisLupusArctos]

Upthesaukee, that is almost exactly what we had. Ice fog. The only difference is, we couldn't throw water into the air and watch it freeze. We knew it was crystals in the air because it happened at night so our headlamps were reflecting back at us in ways they wouldn't if it was normal fog. That would've produced a soft gray/white glow. This produced a sparkly effect, like glitter suspended in the air.

[Mink Islander]

I guess that's the correct spelling.

Found this site with instructions! http://www.scottwinger.com/quinzhee-camping.html

Really pretty cool. I'm thinking Mmmm, build one of these this weekend as a sort of bob house. Have it for the fishing derby. So is it a bobhouse and subject to those rules (tongue firmly in cheek)? Definitely a good idea to build a safety circle with reflectors. Would be an unpleasant surprise for a snowmobile racing along at 10PM. But do you have to have your name on it? Does it need to be off the ice by end of March? LOL! :D

If I bring my Scout Troop out next Winter (this year's booked up with other plans) AND we have the snow to work with, we can try this out.

Another interesting ice effect we saw last weekend was along expansion cracks where moisture had been seeping to the surface there were areas with beautiful crystaline formations along the cracks. Wished I'd had my camera along.

Very interesting thread -- sorry if I've hijacked it a bit.

[CanisLupusArctos]

I have uploaded a video of the experience.

http://www.youtube.com/watch?v=mChlXJXsCS0&feature=channel_page

[Senter Cove Guy]

I have uploaded a video of the experience.

http://www.youtube.com/watch?v=mChlXJXsCS0&feature=channel_page

Checkout the freeze-frame at 34 seconds.

[CanisLupusArctos]

In Eli's silhouette I saw what looked like the Old Man of the Mountain profile, but with the open mouth missing.