For some reason, we've had by far more fog on the farm this year than in any other year we can recall. Doesn't matter the season: we're pulling in fog. I hope it doesn't have anything to do with the fact that I've taken on AWAD as a hobby, fog attracting fog and all that. (My fog--not yours, of course, illustrious company.)

Anyway, cut through the fog to the chase:

I've noticed that even when the fog is nearly impossible to drive through on country roads without being in danger of going off the road, when I hit the interstate, the fog is divided between median and the woods, marshes, farmlands to the right. It appears to be a phenomenon. I drive very slowly on the country roads, but hit the interestate and all is well again.

Is there a name for what happens to the fog when you get to an interstate and the fog appears to be divided--has its avenue of clarity on and above the interstate itself between fog over median to the left and fog over marsh to the right? I've been observing this phenomenon all year and have wondered whether fog specialists may have a term for it.

I have lots of other observations to make about fog, but will save them for a rainy day.

Best regards,
WW

Stab in the dark: Maybe it has to do with the temperature of the asphalt surface? It stays warm because cars drive over it, and it heats the air above it. The warmed air rises, and pushes the fog up a bit? Just an educated guess.

Fog is amazing. I have never experienced fog like in Newfoundland. The other night, I was at my Taekwondo class. The school is up a hill, and has windows so you could see the fog rolling in from the sea towards town. I got in my car and drove home, descending into the ever-thickening fog. When I got home, everything was obscured. You could see our neighbours immediately nearby, but not much else. Generally we have quite a view.

It gets so humid here, while still cold. On really humid days, the carpet is damp, and the CAT gets damp. She's my little furry hygrometer!

It gets so humid here, while still cold.

...which adds a whole nother dimension to the expression, "It's not the heat, it's the humidity!"

Bean,

Your description of the fog from the school on the hill made me recall seeing an old horror film called, The Fog. There were lots of shots of fog rolling in just as you described--only in this film the fog was a killer.

I cannot remember how it turned out. Very foggy on that account. I tend to forget endings to thrillers and punchlines for jokes. I am sure there is some kind of psychological term for this kind of habitual blocking out.

Thanks for your theory. I doubt it would apply here because the interstate isn't traveled that much up around the farm and I wonder whether the little traffic there would heat up the road enough. Just a thought--you could be right since you're a scientist!!

The effect is positively chilling, however, as you speed down the interstate, but take a glance at the marshes on the right, a varitable cotton-eye of white with eery black arms of trees looking like bony fingers about to scratch their nails on a board. At high speed, that mass of white cotton and so many scary arms scratching really gets to me. Better keep my eyes on the road or one day I'll end up in the marshes!

Best regards,
WW

Interesting observation. I'd never noticed that. I've noticed some things, but maybe not the same thing. I don't get a lot of fog where I live now. When we drive to my parents' house in TN, there's often considerable fog on I-75 and many people don't slow down a whit as it bogarts in.

Have you ever seen ice fog? I'm not exactly sure how it's different than regular fog. We used to get ice fog up in Fairbanks. I don't know why they called it that, but it was pretty opaque stuff. Sometimes I could barely make out my hand at the end of my arm and the stop sign 15 or so feet away was completely invisible.


k

as you speed down the interstate

One more question, then: Is the interstate a bit higher than the land around it? (My only experience with USn highways was Montana/North/South Dakota.) I find the fog here tends to "sit" in the valleys. Actually, sometimes it looks like cotton balls, just sitting, all fluffy and thick and white, in the valleys. I guess it's denser than plain old air, and sinks.

Since Robert Frost said that fog comes in on little cat feet, that explains why you have to pussy-foot through it.

Robert Frost

Wasn't that Carl Sandburg? (Though if it were Mr. Frost it would be much punnier! )

The cars on superhighway have hot engines that can raise air temperatures appreciably, causing tiny droplest of moisture to evaporate. Remember how the lanes dry up if previously wet?

More wild guessing - mightn't it also be that there are large objects whizzing down the interstate, creating wind patterns that may blow the fog clear of the lanes? If the fog is as dense as you describe, it's probably not moving much, so the wind from speeding cars could blow it off the road and it would just collect wherever there isn't such wind.

I recognize that this means some people have to go fast before the fog clears, but as we've heard from others here, that happens.

Here in San Francisco, we get plenty of fog, but it tends to be higher up and just cools the area down in the afternoon, rarely creating such a driving hazard. It is beautiful when it comes through the Golden Gate, though, as the Gate forms it into a long, thick bar of fog that extends across the bay, while the sun shines all around it.

The hazard here is the rain - we only get rain in the winter, and each year, when the rains first start, people take no heed of it as they're driving and we seem to have a bunch more accidents on the road. I describe those early rains as "stupidity falling from the sky."

The hazard here is the rain - we only get rain in the winter, and each year, when the rains first start, people take no heed of it as they're driving and we seem to have a bunch more accidents on the road. I describe those early rains as "stupidity falling from the sky."

I think that is generally true for any seasonal change. The first days of winter driving are always treacherous here, until you get used to leaving more distance to stop, remembering not to drive in the ruts, not spinning your tires when starting at a red light, don't brake during a turn (which you can otherwise get away with) etc., etc. I personally HATE winter driving, whether I'm used to it or not!

Have you ever seen ice fog?

FF are you talking about winter fog? When fog forms over snow or ice the water molecules are just this side of freezing. The second they hit something (your windshield as an example) they freeze solid and form a sheet of ice.
Quite inconvenient because you never really have enough windshield spit to last through the whole fog bank and you constantly have to refill reservoir.

Ooo Bean, I LOVE winter driving. Especially though big floofy-flake snow storms. True, people usually slow to a crawl, but you have to be at the peak of attention and I find it invigorating.

Oh I do so love it when someone asks a question about something that I've just read before I forget it.

...far more fog on the farm this year.
No one can rightly question this observation. Even though general statements concerning weather by casual observers are highly subjective and therefore suspect. You were there and we were not. - -
I agree totally with Bean and Bill and Hyla, but let me elaborate on some points that I won't remember next week...

You can't see light. That is until it is reflected off something. In a fog the reflection is provided by little particles of fog, so it would seem that visibility would degrade with distance. It does but in packets, with some colors absorbed first, green and blues first, reds and yellows later. low beam yellow fog lights help ,but in a deep fog the human eye-mind needs a frame of reference in which to judge depth and relative speed. The backdrop of swamp and median would serve to contrast and distinguish the parallel lines of the interstate. More so, a concrete surface would reflect light better than green stuff.
Well isn't that interesting, but it's probably has little to do with what you saw. - -

I've noticed that even when the fog is nearly impossible to drive through on country roads without being in danger of going off the road, when I hit the interstate, the fog is divided between median and the woods, marshes, farmlands to the right. It appears to be a phenomenon.

Radiation fog is the caused by the cooling of the ground at night. This allows evaporation at a lower dew point. The process of evaporation warms the air and radiates the warmth upwards. on clear star filled nights when there are no clouds to reflect the radiation back down to earth, fog is formed. This is probably not what you saw. - -


An Upslope fog is formed when moving air is forced to rise upward over mountains where the atmospheric pressure is less, the air is cooled by expansion and the lowered dew point produces fog on the windward slopes of the mountain. No! -you didn't drive through this. - - Note: The high wet appalachians are the foggiest places in the contiguous states. More so than Oregon. I think.



Evaporation fog occurs when a layer of cold air moves over warm water or warm, moist land surfaces. This results in fog formation as the water evaporates into the cold air. This is probably what you saw.

Is there a name for what happens to the fog when you get to an interstate and the fog appears to be divided.
Good heavens I hope not. If we keep on naming each and every thing and forget our adjectives, our mind will become so cluttered it will be like driving down the interstate in... split-pea-soup. - -

I've had some very foggy days this week too, (fortunately, i don't have to drive, i take a commuter railroad to work,) but as i pass by one of the salt marshes, the fog is a soft mantle of white, drifting across the waters..

the same weather system that is causing the fog in NYC is a front of low pressure, that extents south, and west.. the curved line of this slow moving front extents from south and west of Richmond VA, all the away up to Boston.. it is moving slowly north and east, and i suspect WW, will have heavy thundershowers, tonight, or early tomorrow, they are expecpect to pass through NY about 5 PM tomorrow. and boston early saturday..

the low is filled with hot moist air up from the gulf of mexico, and behind it is a high pressure system the thunderstorms are a 'squall line' where the two systems meet.
skys today are clear blue and cloudless. and some of the fog is radiation fog.. but almost none is evaporation.. we are in the midst of a 17 month drought, and i wish the ground was cool and moist. We (NY) had normal rain fall for the month of MAY, but this is there first time since september 2000! NY and NJ reservois are all way below normal. (NY are at about 81%, not flush from winter run off and at 100%--as they should be.) NJ is in worse shape. the local EPA office is working with city and state agencies to raise public awareness of poor water uses, and to come up with solutions to save water.

the WTC site ate up thousands of gallons.. the fires there burned from sept 11 to November! and the dust from the clean up requires that the city use water trucks to wash down the street (now only 2 times aday, but for months, 4 or more times.)

Wasn't that Carl Sandburg?

Oops, uh, ummm, it's just a mild case of senility, that's all! I was in a fog when I wrote that.

Milum, your post was right on target. Good work! Now, if you want to come out here to Oregon and sample our fog, limmie know!

That would be the stuff, though I don't recall hearing it referred to by that name, it clearly makes sense.

k