What is black ice? After living in MN, my mother thought it was formed at intersections from freezing exhaust. This does not fit with the usual usage in KY. So I thought I’d try to see if anyone out there had any insights.
Ice is clear. Roads are dark. When ice freezes on roads, it is hard to see it while driving. Drivers then drive like normal not realizing they are about to be driving on ice instead of on pavement. That’s when the slipping begins.
Oh boy, my first official case of sig line writer’s block.
Black ice = a thin, hard, transparent covering of ice on the road.
“Black” because it assumes the colour of the road underneath, though it’s not actually black itself.
African-American Ice is the proper term nowadays. 
When danger reared its ugly head,
He bravely turned his tail and fled
In my experiences in Indiana, black ice was to be found lurking in the shadows on cold clear days where you think the road is dry…
And true to form, Murphy always seemed to place it on curves or bridges!
VB
This sigline is closed for renovation.
In the frozen wastelands of Maine it would refer to plain old ice that looked black as it was so clear.
When it’s like that you can see through to the depths which are not getting sunlight so seem very dark/black. The clearness comes from not having flaws like bubbles coming through the ice from below, which make a surface to reflect the light. The sun heats the trapped air and the bubbles work their way higher.
Also, the ice becomes unclear when a clear layer gets overlaid with a light snow which then partly melts then freezes. Then depending on conditions will become bluish, grayish or white, as there is something to reflect sunlight off of.
If a very clear layer gets rained on and quickly freezes the clearness or black looking ice is maintained.
Nope. It’s black. Even on a light gray road.
I live in Minnesota, and I’m very familiar with the stuff. It does form at intersections, driveways, etc.,-- wherever cars have to idle. The exhaust from the cars either condenses or it momentarily melts the ice or snow which then refreezes into a nice, smooth, slippery surface. The cars spinning their tires over it continues the polishing action until it’s as smooth as a mirror.
And talk about frictionless! You can approach a stop sign at 5 mph, touch the brakes, and then experience the adrenaline rush of not slowing down at all as your car transits the intersection unbidden.
And it always seems to happen in such slow motion. Here (in Winnipeg for those of you who haven’t noticed) we have to keep sanding/salting our intersection. It is no fun sliding in to incoming trafic and not being able to do a darn thing about it, except try to steer for a snowbank.
The definition of “black ice” must be a regional thing. I’ve lived mostly on the East Coast and I always understood it to be the very clear ice that forms without bubbles or snowflakes or anything else to make it opaque.
I think of it as being on untreated streets, highways and sidewalks or where run-off has occurred overnight, for example.
Oh, I’m gonna keep using these #%@&* codes 'til I get 'em right.
The definition of “black ice” must be a regional thing. I’ve lived mostly on the East Coast and I always understood it to be the very clear ice that forms without bubbles or snowflakes or anything else to make it opaque.
I think of it as being on untreated streets, highways and sidewalks or where run-off has occurred overnight, for example.
Oh, I’m gonna keep using these #%@&* codes 'til I get 'em right.
Rysdad, All our roads here are black (at least in the cities), so it’d never occurred to me that it might look black on a light-coloured road.
Rysdad: are you saying the ice itself is actually black, in the sense that if you chipped off a piece of it it would like like a chunk of coal?
If so, I’ve never seen anything like that, though the other characteristics you mention… extremely smooth and slippery, with no air bubbles… are in common with what I’ve always called “black ice”. It looks basically the same color as the road does when it’s wet.
Driving to South Dakota once, we stopped to help some people who had slid off the side of the road. When we stopped, we realized we were lucky not to have done the same thing: at one point I put my hands against the side of the van, pushed gently, and slid across one and a half lanes of the interstate (there was basically no traffic at the time).
Yep. Or more accurately, like obsidian. I believe it’s colored that way from the exhaust and general roam scum. It is most definitely not clear.
Encountering black ice is one of the quickest ways to get from bored to holy shit! that I know of.
Hmm. As a lifelong Texan, the only context in which I had heard the term before was in reference to asphalt. The kind that’s really good for rollerblading.
‘Black ice’ is not the color black. I don’t know who is feeding someone hashish to believe that. It is clear ice that usually is very thinly layered, often on top of black asphalt. This definition comes straight from Mirriam-Webster:
See the dictionary at http://www.m-w.com/cgi-bin/dictionary .
rysdad, i lived in the mountains of colorado for 10 yrs & had a wonderfully exciting 40-mile drive home over black ice one christmas afternoon. it included a truly adrenalin-producing sail against & across several lanes of traffic on what is locally known as dead man’s hill.
these are mountain roads w/ no idling cars anywhere. people up there are in a hell of a hurry to get some place else. black ice is common all winter. it comes from parts of the darker pavement absorbing heat, melting the snow enough to nearly dry up, but leaving enough to refreeze in a very dangerous, clear layer.
if the lighter pavement looks dark, it has more to do w/ light reflecting off it in a different way than w/ it being covered by ice that is actually black. i have a little problem w/ imagining you actually dug up a chunk of the stuff to determine it was black as obsidian rather than believing a local UL.
Geez.
I have seen it. I have walked on it. I have done the “mid-winter break dance” on it. I have touched it.
What I am talking about is most definitely, unequivocally, opaque black.
Now…I grant that there may be other types of “black ice.”
One: The kind you get from darker pavements absorbing heat, melting ice or snow, and then refreezing.
Two: Lake ice that is not snow-covered and is relatively clear so that it appears dark.
The black ice with which I’m intimately familiar is the kind I mentioned in my post. Think of it this way…
Take some snow. Add the dirt, oil, sand, salt, scum and dreck from the road. Mix well by driving some cars over it. Add some exhaust…preferably from a bus. The snow melts and is infused with the schmutz. Now re-freeze it. What results isn’t even translucent, much less transparent.
Or, try this experiment. First, find a snow bank (not too easy for some of you, I know). Now, back your car up so that the exhaust is close to the snow bank and pointed at it. Let your car idle for a while. Fifteen to twenty minutes should do it. Now check the snow bank. You’ll find a hollow area that is coated with some black residue. That’s black ice in its purest form.
UL my foot. Maybe you haven’t experienced what I have.
Those that doubt the existence of black ice risk a cracked coccyx or a call to Maaco.
In Canada black ice is the protective layer covering the road for 9 months of the year that stops your wheels from wearing away the asphalt underneath.
I’ve done an extensive search for a definition of black ice. (My own state’s DOT says it’s invisible.) I emailed a local TV station’s meteorologist (and got a quick response!), and he said that it:
-
Is caused by what I said it was
-
Is not invisible.
-
Is clear and it’s just the color or the road showing through.
sigh
It hasn’t been cold enough lately for black ice to form so I haven’t seen any. But if it does get bitterly cold again, rest assured I will take the opportunity to chip off a chunk and inspect it. I can’t be misremembering 46 winters of shoe skating through crosswalks.
<giggling at the thought of poor Rhysdad learning firsthand the fun of contradictory answers from experts, with which Uncle Cecil struggles daily!> 