Black Ice | WEDGE ISSUE WARNING
#51
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I think that is insightful and so true. I actually took my 9 year old out on the bike during the last snowfall expressly to teach him about locking up the rear, powersliding, fishtailing and that kind of stuff. He rides somewhat, like with us on errands or to school, but he really doesn’t go out and play on his bike like I used to. He’s very much a kid of the computer era, if you know what I mean.
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#52
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and yes, the greasy nature and lots of snow was super hard to ride in, front end going all over the place so often and just a lot of work. Had to hike a bike through and over deep stuff, and easily twice as long to go the same distance.
These conditions on narrower studded tires don't help much, my old 2.5inch mtb tires would have been better, fat bike better but I'm not leaving it locked up and getting salty.
but it's always the same thing, it's a fun challenge to see if you can go on a snowstorm day, ski goggles but still using bike helmet to have mirror. Handy when sidewalk is unplowed and road is better, so you can easily watch for cars coming behind and get off the road.
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yeah, gotta keep yer sense of humor on a bike
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should the title of thread have the spelling like this: "wedgie"
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#57
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right you are. this is from a cpl yrs ago. I cringe every time I watch it
https://youtu.be/kuQpYZPUf3s
https://youtu.be/kuQpYZPUf3s
I love the way the bike is still sliding afterwards.
reminds of crashing in the wet the first time I was on a wet practice session on track back eons ago when I spent a summer motorcycle circuit racing. Had too much tire pressure, locked the front and chucked it. Sliding along on my back, listening to the sounds of my bike scraping along in front of me, all I could think of was, " &^$^#! I'm ruining my rain suit !!" Wasn't hurt, but learned to be more careful of tire pressures, mind you, never raced in the rain, but did manage to toss it into the weeds a number of times in the dry.
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dont know if thats you, but that ice was preeeety darn smooth and I guess we all learned once not to go onto ice like that without studded tires.
I love the way the bike is still sliding afterwards.
reminds of crashing in the wet the first time I was on a wet practice session on track back eons ago when I spent a summer motorcycle circuit racing. Had too much tire pressure, locked the front and chucked it. Sliding along on my back, listening to the sounds of my bike scraping along in front of me, all I could think of was, " &^$^#! I'm ruining my rain suit !!" Wasn't hurt, but learned to be more careful of tire pressures, mind you, never raced in the rain, but did manage to toss it into the weeds a number of times in the dry.
I love the way the bike is still sliding afterwards.
reminds of crashing in the wet the first time I was on a wet practice session on track back eons ago when I spent a summer motorcycle circuit racing. Had too much tire pressure, locked the front and chucked it. Sliding along on my back, listening to the sounds of my bike scraping along in front of me, all I could think of was, " &^$^#! I'm ruining my rain suit !!" Wasn't hurt, but learned to be more careful of tire pressures, mind you, never raced in the rain, but did manage to toss it into the weeds a number of times in the dry.
re: your story. cat-like reflexes & stayed pliable
Last edited by rumrunn6; 01-19-22 at 07:54 AM.
#59
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bading baboom, its always that fast aint it? I'll touch wood a few times just we are bringing falling up here.....Rode on this frozen river last winter, you can see someone had been out on their skates. Had to be careful though like I wrote earlier cuz my studded tires are the econo versions and have only so many studs, so had to be careful not to lean. ( but perfect for my commuting generally)
Was a real laugh though.
PS, it was completely frozen, it looks like open water, but the ice was just wavey ish in places, quite thick ice everywhere. Shot is overexposed so it looks like water.
Was a real laugh though.
PS, it was completely frozen, it looks like open water, but the ice was just wavey ish in places, quite thick ice everywhere. Shot is overexposed so it looks like water.
#60
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whelp ... Minnesota decided to prove that refreeze and black ice isn't an either-or situation. Yesterday afternoon was sunny 40F/4C, so much melting; then the temps fell off a cliff dropping to -2F/-19C in 12 hours. Now we have tons of refreeze and conditions for black ice too. In other words, great day to ride studded bike tires!
Last edited by Hypno Toad; 01-20-22 at 07:33 AM. Reason: typo
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whelp ... Minnesota decided to prove the refreeze and black ice isn't an either-or situation. Yesterday afternoon was sunny 40F/4C, so much melting; then the temps fell off a cliff dropping to -2F/-19C in 12 hours. Now we have tons of refreeze and conditions for black ice too. In other words, great day to ride studded bike tires!
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#62
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So perhaps you won't see "refreeze" ice on the road on a 25F morning, but be careful if it's down to 20F, because it's possible then. (And be careful in situations like Virginia on I-95, when it was impossible to pre-treat the road surface because it was raining while it froze!)
#63
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If you don't live in a place where the high temp is 0F/-18C; you're safe from black ice and this thread (and yes, I'll be going out for a ride today):
#64
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Refreeze ice looks like wet pavement (like the video in the OP); however, with temps below zero F, black ice does not look like wet pavement, you can't see the difference between black ice and dry pavement.
If you don't live in a place where the high temp is 0F/-18C; you're safe from black ice and this thread (and yes, I'll be going out for a ride today)
If you don't live in a place where the high temp is 0F/-18C; you're safe from black ice and this thread (and yes, I'll be going out for a ride today)
I'm genuinely curious what organization developed the definition / differentiation and why current meterologists don't follow that?
Last edited by gpburdell; 01-25-22 at 09:31 AM.
#65
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Refreeze ice looks like wet pavement (like the video in the OP); however, with temps below zero F, black ice does not look like wet pavement, you can't see the difference between black ice and dry pavement.
If you don't live in a place where the high temp is 0F/-18C; you're safe from black ice and this thread (and yes, I'll be going out for a ride today)
If you don't live in a place where the high temp is 0F/-18C; you're safe from black ice and this thread (and yes, I'll be going out for a ride today)
I'm genuinely curious what organization developed the definition / differentiation and why current meterologists don't follow that?
Edit: adding link to local news story on the topic: https://minnesota.cbslocal.com/2021/...-temperatures/
Last edited by Hypno Toad; 01-25-22 at 09:18 AM.
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local Massachusetts roads at lunchtime, getting my oil changed. that's liquid water, not ice
our weather ppl are offering 4 choices
snow showers
snow
snow/wind
blizzard
our weather ppl are offering 4 choices
snow showers
snow
snow/wind
blizzard
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#67
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Re that photo. Here the roads look like that at freezing or even -15c (? F) because so much road salt is used, a briney liquid is often all over and when it gets thrown up on the bike, it freezes right away and really makes a mess.
this is why I wash my bike after every ride. 5 mins and its done.
this is why I wash my bike after every ride. 5 mins and its done.
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Nope. Ice is ice. It is solid water.
Nope. Not at all. “Black ice” is the motorist equivalent of a JRA. I know that people up in your neck of the woods are fed this completely incorrect idea that car exhaust will freeze and cause an “invisible sheet of ice” to form by their local media but that is incorrect. You might have ice forming from condensed water flowing out of the tail pipe but the uncondensed water vapor will be present in enough volume nor in still enough air to condense out of the air and form an “invisible sheet of ice”.
A sedan has a frontal area of about 20 sq feet. At 10 mph, a car covers 880 feet per minute. At 20 mph, a car covers 1700 feet. Pushing a car though at 10 mph through the air results in displacement of 18,000 cu ft/min of air. At 20 mph, the car displaces 38,000 cu ft/min. And it only gets worse with increased speed. This results in a very high turbulent flow behind the car.
Now, let’s consider how much water vapor is available. When burned, a gallon of gas results in a gallon of water produced (about 4000g of water). That gallon of gas is spread out over the MPG of the vehicle. Let’s assume, because of the cold, that the car is getting 15 mpg. That 79,000 feet. Over each foot of the car’s travel, the car produces 0.05g of water. For the 10 mph example, the car is producing 44g of water but that is mixed into 18,000 cubic feet of air. That’s 2.4 µg of water per cubic foot. That’s not much.
Additionally, most people who crash a car on ice aren’t doing so at an intersection. Most all of the reports of “black ice” accidents are of the “I was just driving along, hit a patch of black ice and the car spun out of control” variety.
To “salt”. The ability of a salt to melt ice depends on the identity of the “salt”. Sodium chloride stops being effect around 20°F. Magnesium chloride stops being effective around 0°F. Calcium chloride stops being effective around -25°F. Departments of transportation know these values and will use a product that is more effective when necessary.
It’s still a transparent and is still referred to as “black ice” and is still used as an excuse for not paying attention.
There is nothing in your video to suggest that the ice you crashed on is “referees” or “in the shady part”. At 5 seconds you can clearly see the sun reflecting off of what appears to be a wet road. After that, the road appears to be wet. That is my problem with the whole “black ice” and “it was invisible” argument. It is very clear in your video that it was cold and the road appeared to be wet. You should have expected ice.
Black ice is unique in temps below 0F (-18C): Black ice happens when motor vehicles are stopped and idling, the exhaust warm snow & ice on the road surface. When the vehicles moves on, the melt freezes quickly. Road salt is not effective at these temps and black ice is common at stop lights and on road after rush hour congestion. It is near impossible to see black ice (and the reason for the name).
A sedan has a frontal area of about 20 sq feet. At 10 mph, a car covers 880 feet per minute. At 20 mph, a car covers 1700 feet. Pushing a car though at 10 mph through the air results in displacement of 18,000 cu ft/min of air. At 20 mph, the car displaces 38,000 cu ft/min. And it only gets worse with increased speed. This results in a very high turbulent flow behind the car.
Now, let’s consider how much water vapor is available. When burned, a gallon of gas results in a gallon of water produced (about 4000g of water). That gallon of gas is spread out over the MPG of the vehicle. Let’s assume, because of the cold, that the car is getting 15 mpg. That 79,000 feet. Over each foot of the car’s travel, the car produces 0.05g of water. For the 10 mph example, the car is producing 44g of water but that is mixed into 18,000 cubic feet of air. That’s 2.4 µg of water per cubic foot. That’s not much.
Additionally, most people who crash a car on ice aren’t doing so at an intersection. Most all of the reports of “black ice” accidents are of the “I was just driving along, hit a patch of black ice and the car spun out of control” variety.
To “salt”. The ability of a salt to melt ice depends on the identity of the “salt”. Sodium chloride stops being effect around 20°F. Magnesium chloride stops being effective around 0°F. Calcium chloride stops being effective around -25°F. Departments of transportation know these values and will use a product that is more effective when necessary.
Refreeze ice is commonly called black ice, but it's different. Refreeze happens on milder, sunny days; and when day temps are above freezing and nights are blow freezing. Refreeze ice isn't typically an issue on road surfaces because road salt and traffic won't let ice form. But refreeze is an issue on the shoulder of roads, bike trails, and bridge decks.
Why does it matter ... ice is ice, right? From the saddle of a bike it matters because you want to know when and where to look for ice that will be hard to see. For example, this morning it's -20F (-29C) and I'm riding to work, when riding in the traffic lane coming up to a stop light there's a good chance of ice being on the road surface. Approach the red lights with extra stopping distance and be aware of people in cars not doing the same. OTOH I'm riding to work when it's 25F (-4C), the day before was sunny and temps above freezing, I need to look for ice on shoulders and on bike only trails as well as shady areas.
Refreeze example, I was not riding winter tires, and I turned in the shady part of the road and took a fall (and a reminder to use the winter bike)
Refreeze example, I was not riding winter tires, and I turned in the shady part of the road and took a fall (and a reminder to use the winter bike)
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#69
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OMG ... I'm so happy to see you posted a comment to this thread, I was getting worried about your welfare!
Funny that anybody in this thread that IDs on BF as location MN has agreed with me .... but I know exactly one person that is fed up with this information about black ice, and he doesn't live in Minnesota. Additionally, local journalists do not agree with you, did you see this post and read it? How Does Black Ice Form In Subzero Temperatures? https://minnesota.cbslocal.com/2021/...-temperatures/ (hint: you've over focused on exhaust vaper, it's part of the equation, but not whole story).
I'm happy to let you have a simple definition for black ice, OTOH for me and my riding (and driving), I will be aware that ice can form in different locations based on the conditions. This makes me a safer road user, and I can't understand how somebody gets fed up with that.
I'm happy to let you have a simple definition for black ice, OTOH for me and my riding (and driving), I will be aware that ice can form in different locations based on the conditions. This makes me a safer road user, and I can't understand how somebody gets fed up with that.
#70
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an old friend of mine just bought a (real POS btw) "winter bike" cuz she wants to try winter biking. I got her some studded tires and the bike is ready to go.
I do worry about her (and now we come to the connection to this topic) because she's just a so so bike rider, a pretty so so skier.
To the most important thing about winter riding and dealing with ice and or the myriad of surface conditions, is being very observant and being experienced in knowing that X surface probably has X traction, and adjusting ones speed, lean angle, braking details (front, back,how much, none at all etc).
On top of this, she didnt spend her youth goofing around on bikes, sliding, crashing, you name it like most of us did, nor sliding in cars etc. So basically told her all of this and warned her to be slow and observant, but that yes, she is going to fall down sometimes when not paying attention.
I hope she picks up the skillset well enough and learns from all the traction / lack thereof situations that will happen.
I also just hope she doesnt hurt herself, she's getting on like a bunch of us. Not fun at 25 or 30, but less fun at 60.
I do worry about her (and now we come to the connection to this topic) because she's just a so so bike rider, a pretty so so skier.
To the most important thing about winter riding and dealing with ice and or the myriad of surface conditions, is being very observant and being experienced in knowing that X surface probably has X traction, and adjusting ones speed, lean angle, braking details (front, back,how much, none at all etc).
On top of this, she didnt spend her youth goofing around on bikes, sliding, crashing, you name it like most of us did, nor sliding in cars etc. So basically told her all of this and warned her to be slow and observant, but that yes, she is going to fall down sometimes when not paying attention.
I hope she picks up the skillset well enough and learns from all the traction / lack thereof situations that will happen.
I also just hope she doesnt hurt herself, she's getting on like a bunch of us. Not fun at 25 or 30, but less fun at 60.
#71
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Funny that anybody in this thread that IDs on BF as location MN has agreed with me .... but I know exactly one person that is fed up with this information about black ice, and he doesn't live in Minnesota. Additionally, local journalists do not agree with you, did you see this post and read it? How Does Black Ice Form In Subzero Temperatures? https://minnesota.cbslocal.com/2021/...-temperatures/ (hint: you've over focused on exhaust vaper, it's part of the equation, but not whole story).
“When traffic slows down a lot or even stops in some areas, even your exhaust, it can drip and those droplets then freeze and create black ice,” said Meyer.
I'm happy to let you have a simple definition for black ice, OTOH for me and my riding (and driving), I will be aware that ice can form in different locations based on the conditions. This makes me a safer road user, and I can't understand how somebody gets fed up with that.
The reason I’m fed up with the term is that it’s used as a “get out of jail (or responsibility)” card.
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#72
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Missing the point. A thin veneer of moisture is already on the road. The H2O doesn't necessarily come from the exhaust.
And sorry, Denver isn't really that cold. Your average low temperature in January is warmer than our average high:
Denver: January average high-temperature 40.5°F, average low-temperature is 21.6°F."
Minneapolis January average high temperature 20.3 °F, average low temperature 7.5 *
And sorry, Denver isn't really that cold. Your average low temperature in January is warmer than our average high:
Denver: January average high-temperature 40.5°F, average low-temperature is 21.6°F."
Minneapolis January average high temperature 20.3 °F, average low temperature 7.5 *
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#73
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The water on the road (which looks wet but Surprise! Surprise! Surprise! it’s ice!) comes from some atmospheric event. Either snow that has melted or drizzle that has frozen or rain that has frozen. Those atmospheric events may pull the water from the exhaust down with them but the contribution from that water of combustion is insignificant to the formation of “black ice”.
And sorry, Denver isn't really that cold. Your average low temperature in January is warmer than our average high:
Denver: January average high-temperature 40.5°F, average low-temperature is 21.6°F."
Minneapolis January average high temperature 20.3 °F, average low temperature 7.5 *
Denver: January average high-temperature 40.5°F, average low-temperature is 21.6°F."
Minneapolis January average high temperature 20.3 °F, average low temperature 7.5 *
On the other hand are you going to do the same analysis on everyone else posting here? Boston? 37°/22°F. So does Rumrunner6 not now what cold weather is? That’s a very similar temperature range to Denver’s.
How about sweeks in Chicago? 31/18°F. Or Grain Brain in central Iowa? (Des Moines) 30/13°F. Both are warmer than you experience but I doubt anyone would say they don’t know what cold weather is.
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Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Last edited by cyccommute; 01-31-22 at 12:08 PM.
#74
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Not sure if that is directed towards me or not. I agree that the thin veneer of moisture is already on the road. The road looks wet but people seem to assume that it is only water. Thus they are surprised when they discover physical chemistry. The water doesn’t come from exhaust. There’s simply not enough water in the exhaust…and the air mixed with the exhaust from the car moving through the air…for it to cause icing problems at intersections or on the open road.
The water on the road (which looks wet but Surprise! Surprise! Surprise! it’s ice!) comes from some atmospheric event. Either snow that has melted or drizzle that has frozen or rain that has frozen. Those atmospheric events may pull the water from the exhaust down with them but the contribution from that water of combustion is insignificant to the formation of “black ice”.
Now you are missing the point. No, we aren’t as cold as Minneapolis but we have wider fluctuations and we do experience cold weather on occasion. We get 60°F days here but we also get subzero days…often from one day to the next. We can even experience 60°F swings within a few hours. We likely have greater experience with melt water refreezing than you do further north.
On the other hand are you going to do the same analysis on everyone else posting here? Boston? 37°/22°F. So does Rumrunner6 not now what cold weather is? That’s a very similar temperature range to Denver’s.
How about sweeks in Chicago? 31/18°F. Or Grain Brain in central Iowa? (Des Moines) 30/13°F. Both are warmer than you experience but I doubt anyone would say they don’t know what cold weather is.
The water on the road (which looks wet but Surprise! Surprise! Surprise! it’s ice!) comes from some atmospheric event. Either snow that has melted or drizzle that has frozen or rain that has frozen. Those atmospheric events may pull the water from the exhaust down with them but the contribution from that water of combustion is insignificant to the formation of “black ice”.
Now you are missing the point. No, we aren’t as cold as Minneapolis but we have wider fluctuations and we do experience cold weather on occasion. We get 60°F days here but we also get subzero days…often from one day to the next. We can even experience 60°F swings within a few hours. We likely have greater experience with melt water refreezing than you do further north.
On the other hand are you going to do the same analysis on everyone else posting here? Boston? 37°/22°F. So does Rumrunner6 not now what cold weather is? That’s a very similar temperature range to Denver’s.
How about sweeks in Chicago? 31/18°F. Or Grain Brain in central Iowa? (Des Moines) 30/13°F. Both are warmer than you experience but I doubt anyone would say they don’t know what cold weather is.
Akron, OH
Weather averages
Overview
Graphs
Month High / Low(°F) Rain
January 34° / 21° 8 days
February 36° / 23° 7 days
March 47° / 31° 9 days
#75
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Since we are going into a totally unrelated rabbits warren (I mean of course we are, there is a commuter posting to the thread... we are certainly going to get way off topic)
Reference: https://en.wikipedia.org/wiki/Climat...al_climatology
Nobody thinks Minneapolis is the only place that gets cold ... but there are few large cities (Canada has most of the others) that have extended periods of sub-zero (F) temps. Getting down to 0F/-18C for a night is cold ... but going 4-5 days without getting above 0F/-18C, that's definitely a different level of cold.
And since we are totally off topic, my buddies are up riding the Arrowhead 135 yesterday and today ... They start at International Falls (Frostbite Falls for all the Rocky and Bullwinkle fans), they have gone 2 weeks (14 days) without temps getting above 0F/-18C (I know, I know ... that was back when my grandpa was in diapers).
Lastly, there is somebody in this thread that is hyper-focused on one contributing factors to sub-zero black ice forming on road surfaces, and sure that single source wouldn't likely be enough to create enough ice to cause traction issues, yet it is clearly one of the contributing factors. This information was posted last week as a link, but I've copied text and added it to the tread to help those that just scrolled past the link:
Reference: https://minnesota.cbslocal.com/2021/...-temperatures/
Going way back to the OP, if you're riding a bike during a sub-zero cold snap, you'd look out for black ice at stop lights, in the traffic lanes, where the stopped/idling cars create the conditions that will melt any water on the road surface (and add some exhaust vaper too). Moreover, the highways may be treated with better ice-melt chemicals, but you won't likely see that same treatment on the side streets where a person would ride a bike.
The climate of the Twin Cities is classified as hot-summer humid continental without dry season (KöppenDfa).[2] A feature of the humid continental climate in the United States is that weather can be unpredictable with extremes occurring in many phases of measurements. For example, the Twin Cities has a hotter all-time record high temperature of 108 °F (42 °C) than the entire state of Florida, despite being located nearly 1000 miles farther from the equator. Conversely, temperatures during the winter months are colder in the Twin Cities than in any other major metropolitan area in the continental United States, and are about equal to those in Anchorage, Alaska, which is around 1,000 miles (1,600 km) closer to the North Pole. The Twin Cities can also experience droughts, floods, and on average are windier than Chicago, Illinois (the "Windy City", although that is not the origin of the phrase).
Nobody thinks Minneapolis is the only place that gets cold ... but there are few large cities (Canada has most of the others) that have extended periods of sub-zero (F) temps. Getting down to 0F/-18C for a night is cold ... but going 4-5 days without getting above 0F/-18C, that's definitely a different level of cold.
And since we are totally off topic, my buddies are up riding the Arrowhead 135 yesterday and today ... They start at International Falls (Frostbite Falls for all the Rocky and Bullwinkle fans), they have gone 2 weeks (14 days) without temps getting above 0F/-18C (I know, I know ... that was back when my grandpa was in diapers).
Lastly, there is somebody in this thread that is hyper-focused on one contributing factors to sub-zero black ice forming on road surfaces, and sure that single source wouldn't likely be enough to create enough ice to cause traction issues, yet it is clearly one of the contributing factors. This information was posted last week as a link, but I've copied text and added it to the tread to help those that just scrolled past the link:
How does black ice form throughout subzero temperatures? Anne Meyer, spokesperson for the Minnesota Department of Transportation, said the first aspect was the gentle snowfall.
“That was enough to give those tires something to melt when they were driving during the commute,” she said.
Then the cold quickly froze the melted snow, creating a thin, slick sheet on the pavement that drivers often can’t see. If the snow had fallen midday when the sun was in the sky, it likely would have stayed in liquid form until nightfall.
“If the snow would have happened overnight on the weekend, we would have had less traffic and as a result less areas of icy terrain,” Meyer added.
Bridges and overpasses are often trouble spots for black ice since cool air circulates above and below, chilling the pavement. Intersections can also be tricky.
“When traffic slows down a lot or even stops in some areas, even your exhaust, it can drip and those droplets then freeze and create black ice,” said Meyer.
“That was enough to give those tires something to melt when they were driving during the commute,” she said.
Then the cold quickly froze the melted snow, creating a thin, slick sheet on the pavement that drivers often can’t see. If the snow had fallen midday when the sun was in the sky, it likely would have stayed in liquid form until nightfall.
“If the snow would have happened overnight on the weekend, we would have had less traffic and as a result less areas of icy terrain,” Meyer added.
Bridges and overpasses are often trouble spots for black ice since cool air circulates above and below, chilling the pavement. Intersections can also be tricky.
“When traffic slows down a lot or even stops in some areas, even your exhaust, it can drip and those droplets then freeze and create black ice,” said Meyer.
Going way back to the OP, if you're riding a bike during a sub-zero cold snap, you'd look out for black ice at stop lights, in the traffic lanes, where the stopped/idling cars create the conditions that will melt any water on the road surface (and add some exhaust vaper too). Moreover, the highways may be treated with better ice-melt chemicals, but you won't likely see that same treatment on the side streets where a person would ride a bike.