Hacker News Reader

Comment by CivBase | Hacker News Reader

Many places in the midwest have actually switched away from using salt to melt snow because it does a lot of damage to concrete and vehicles. Sand is a popular alternative, but frequent ploughing is often enough to keep main roads clear. Raised vehicles like trucks and SUVs are also much more common in the midwest to avoid getting stuck in the snow.

> America tends to operate in just-in-time style inventory models instead of managing risk by storing surpluses of critical commodities

I don't think this a particularly fair criticism. Deicing salt works by absorbing moisture as it lands, before it can form a sheet of ice. It's useless if it gets wet before you use it. It's pretty dry in the midwest during the winter, but humidity spikes in the summer making deicing salt difficult to store in the off-season. Climate-controlled storage is expensive and deicing salt is quite heavy and bulky.

View on HN

> Deicing salt works by absorbing moisture as it lands, before it can form a sheet of ice.

That's...false? Salt gets spread on existing ice to melt it all the time. Where does the absorbed water go in this model? This assertion is so confusing.

As someone who grew up in a cold climate, the way I recall it is that the salt lowers the freezing point of water by forming a brine, allowing it to run off the road and/or be evaporated by the sun.

It's not quite as straightforward as "yes it does" / "no it doesn't." There's a temperature at which it's too cold for salt to work, and a great deal of the benefit of salt comes from friction as cars drive over it, crushing pieces of ice and forming that slush we all know and love, even at temperatures where it won't actually melt the ice.

> There's a temperature at which it's too cold for salt to work

Sure, brine has a freezing point.

> a great deal of the benefit of salt comes from friction as cars drive over it, crushing pieces of ice and forming that slush we all know and love, even at temperatures where it won't actually melt the ice.

What do you think slush is? It has liquid in it, and that's not molten salt.

> a great deal of the benefit of salt comes from friction as cars drive over it

You may have never tossed a handful of rock salt on steps that have a quarter-inch of ice on them and watch holes actually form in the ice within a half hour or so.

On thin ice, you can watch it form in real time!

Again, it's temperature dependent. Salt lowers the freezing point of water about 4 degrees (either units). Typically when it snows, it is close to freezing (if warmer it would rain, if much colder there wouldn't be enough moisture in the air for precipitation) so adding salt will melt the ice, but there's plenty of time when it's not in that narrow temperature range.

> before it can form a sheet of ice.

I think the person is just saying that pre-emptively salting the road (before snow/freezing rain actually lands) provides some additional level of safety because the road might spend less time with a frozen coating (as opposed to salting only after the surface is frozen over).

>Many places in the midwest have actually switched away from using salt to melt snow

They use salt to melt ice. They plow snow. The only times I've seen the midwest US use sand instead of salt is when the temperatures are below where salt is still effective.

Do you have a citation for this statement, because it is 100% the opposite of what I see in my day-to-day life.

Some area's won't be allowed to use salt, I know in Issaquah in Washington state they could not use salt upon the roads due to laws to protect the salmon streams.

Probably a fair few area's in which salt is prohibited for road use due to such things. So sand makes sense and for some that is all they will see in their area.

In the Seattle area, which Issaquah is part of, they use Sugar Beet Juice. Theres an interesting little article on it here: https://www.king5.com/article/news/local/bellevue/unique-mix....

(To help keep the salt stuck to the road instead of blowing away.)

To me, this is a much more restrictive claim than the original.

How much persistent snow does Washington state get though? The discussion is most relevant for places where snow falls and will stay where it is for months if something is not done.

Quite a lot, especially at higher elevations.

Issaquah is in the Puget Sound region, not the mountains. It has about as much snow as Seattle; i.e., some but not very much.

> How much persistent snow does Washington state get though?

At elevation, of course there's some that's persistent, but that's not much of the state at all. eg Crystal Mountain has snow in the winter, but is completely bare by the summer.

That's not even kinda the Midwest.

When you live in a coastal city everything outside the beltway is the midwest

That is pretty ironic that salmon are at risk of salt given they are famous for adjusting to the ocean. Even though they are essentially already terminally ill and falling apart when they head back into the river to spawn.

This may be about the other end of the cycle? The salt might harm microscopic things that salmon fry eat on their way downriver.

I presume the snow/ice was just a mixup, don't think there is much point arguing about it.

Yes, when I grew up in Sweden salt was everywhere as well. Then before I moved away the forbid salt in some places and replaced it with sand. If I recall correctly, erosion on cars and the effect on local fauna being the reason. I mostly saw sand being used instead of salt at that point. Now I don't know how it looks, as it was a couple of years ago, but I expect sand to be used even more now than before, as the country is getting more focused on ecology and sustainability.

In stockholm they use this relatively fine gravel now (at least the last 4 years I've been to Sweden in the winter). It's absolutely bloody annoying to walk on (and drag luggage near). But I suppose it's there to help the cars maintain traction in the ice/snow.

And I suppose you could sweep it back up again after the fact, etc. (there are piles of it left in areas for easy distribution I assume).

We use a mix by me. Sand goes for most stuff. Hills and dangerous intersections get salt. I think salt costs several times what sand costs, so it is only used where deemed necessary.

Madison WI still uses salt, but we also use a lot of a mixture of sand and salt, which looks like pure sand from a distance, and liquid salt solution sprayed directly on dry roads before snowstorms when possible. The city claims that both of these methods, while not eliminating salt, greatly reduce its use.

The city also puts out piles of sand-salt for residents to use, so I usually grab some at the start of the winter. The mixture is easier to store than either sand or salt by themselves. For instance, a pile of salted sand won't freeze solid.

Salt works by freezing point depression. You can throw salt on sheet ice and it will melt the ice, until it gets too cold. Calcium chloride works to even lower temperatures.

Does putting all this salt on the sidewalks and driveways of your house affect plants around your house? I would imagine that over the years the salt buildup in the soils around everyone’s house would be immense. In ancient times they would salt enemies agricultural land to prevent plants from growing. Do plants not grow near to sidewalks and driveways in the Midwest?

Plants grow anywhere in the Midwest, just not the ones you want. ;-)

Yes to some extent. We actually use the sand/salt quite sparingly, because shoveling usually takes care of things. Just a bit on the front steps, and in a couple places where it tends to ice up on the sidewalks in late winter.

Probably the main source of salt is what gets thrown from the street by the plow trucks.

The lot slopes down towards the street, which helps, and what happens to the grass on the boulevard, we basically don't care. The weeds seem happy enough. The University of Wisconsin has actually developed varieties of trees that are resistant to salt, and we have those varieties out front.

At my workplace they salt more heavily, and have had to re-sod the grass near the walkways. But I think that's the result of several factors, including over-fertilizing during the summer, and maybe having a variety of grass that's less salt tolerant than our weeds. We also don't fertilize or water our lawn.

Up here in the Fox Valley we've been using brine and selectively salting roads to reduce salt usage. There are concerns about sand usage adding sediment to storm drains and into Winnebago, but I think the same applies to salt as well.

> I don't think this a particularly fair criticism. Deicing salt works by absorbing moisture as it lands, before it can form a sheet of ice. It's useless if it gets wet before you use it

Over here deicing is frequently done with brine because it sticks better to the road and doesn't get blown away, so I'm very skeptical about the salt being useless when it's wet.

To add to this, there was a piece on NPR a few days ago where they talked about brine as a more environmentally friendly option to rock salt. De-icing salt gets into lakes and streams, and with brine you need much less salt to achieve the same results apparently.

The point was that rock/crystal salt is useless if it gets wet, because then it can't be reasonably used/moved/broadcast. If it turns into giant bricks of salt, it's impossible to work with.

When dry salt is disolved by water, it is brine.

My late father worked in the salt industry. There is no cost effective substitute for salt. Sand is used for traction purposes, not to melt ice.

There are a number of chemicals that will melt ice though not as well as salt. But these alternatives are much more expensive, they get talked about a lot but haven't made a dent in salts market share.

Similarly, in the northwest salt actually becomes a liability when temperatures are well below freezing. Using salt can actually increase the incidence of more compact, harder-to-see ice (aka black ice) because of the slight thawing and refreezing.

All our county plow trucks scatter gravel behind them. Only businesses seem to sprinkle salt around their entrances.

I don’t think public works and highway departments can really say “just get an SUV lol” unless they’re really rural. Plenty of small cars on the road in Milwaukee, Chicago, Minneapolis, etc.

Yeah, even in smaller towns there are a ton of people with Civics, Neons, and Saturns, and they have to get through all winter. You do need to carry a shovel in case the plow leaves a berm across your street or driveway apron though.

The remaining ones not destroyed by road salt rust.

Too late to edit, but now I understand why people on here use footnote numbers instead of asterisks. oops

My Civic does just fine in Michigan. The only time I got stuck was the one winter I didn't have snow tires.

SUVs actually often have worse traction because the larger tyres are more expensive so some buyers go with a single set of all-weather instead of a proper M+S tyre in winter.

I don't think I've ever met a non-enthusiast who had both summer and winter tires. Is that actually a thing? Maybe in the mountains? Here in Iowa, everything is pretty straight and flat, so you just need to leave more room to slow down.

I have winter tires for my Prius in Indiana. Makes a world of difference and I only use the snow tires for a month or two so they last a long time. The recommended tires on a Prius are these low-rolling resistance tires that are downright treacherous on snow.

Our Civic had some premium Michelin tires on it when we got it. They had zero traction in the winter. Slid through far too many intersections and was all too happy to see them go.

I have winter tires on because it’s the law 4-5 months per year but this isn’t the US. People in the north here use studded tires. Driving with summer tires in winter is extremely slippery, tires makes much more difference than road prep!

It's useless if it gets wet before you use it

It's fine if it's wet as long as it can still be spread by the spreader. In fact, there has to be some moisture in order for the salt to lower the freezing point. It can't mix easily with frozen ice that has no free moisture.

"Pre Wetting" salt is actually a tactic used for snow/ice mitigation for this exact reason.

> "...but humidity spikes in the summer making deicing salt difficult to store in the off-season. Climate-controlled storage is expensive and deicing salt is quite heavy and bulky."

to provide some color, just-in-time doesn't literally mean holding no inventory and perfectly matching inflows to outflows. it means that stores of inventory and intermediate work product are minimized as much as possible in light of the typical mean and variance of a process, but not more than that.

in the case of a town, that means you'd likely size the salt store to be one storm's worth of salt and then trigger a replenishment as soon as a storm is imminent (just in time; that is, when necessity is established, but no sooner). you'd also likely try to deplete the store at the end of a storm season and replenish a storm's worth at the beginning of the next.

That's assuming you can get salt in time for the storm, or even at all at that point. At least on the consumer side, a lot of the manufacturing facilities that produce deicing salt switch over to producing fertilizer around new year's. A year or two ago we had a late winter storm and all of the stores in the area were out, and their warehouses too.

yes, good point. we base our statistical inferences on backward-looking data, but the future can change in ways we're unable to fully predict and account for.

this illustrates that just-in-time isn't an unalloyed good. it trades off resiliency for cost (and a bit of agility). it also introduces more structural variance in the supply chain, exacerbating supply issues, which isn't obvious on first blush (operations research coursework covers this).

>> salt to melt snow

Who does that? Salt is used to melt ice, not snow.

>>Raised vehicles like trucks and SUVs ... to avoid getting stuck in the snow.

"Raised" vehicles are not tall because of snow. That clearance is for off-road driving, not snow on a road. Any public road would be closed long before snow became so deep as to actually require a car to have greater ground clearance. If anything, a taller vehicle is more of a liability on a slippery road. The ideal vehicle for winter on road driving is any 4WD/AWD car with some good snow tires and a modern traction control system.

The ideal vehicle for slippery conditions is actually rear wheel drive, with ABS brakes. RWD means that everything you do reminds you that it is slippery and so you never get going fast. 4wd/awd means that you get going fast enough that you end up well into the ditch instead of just stopped on the side of the road where you can push yourself out without a tow truck.

The above is partially tongue in cheek, but there is a point worth thinking about.

The ideal vehicle for any given amount of traction is going to look pretty close to the same regardless of the amount of traction.

Tell me you live in SoCal without telling me you live in SoCal.

Canada. BC and Alberta, the north bits. Wet mountain snow. -40 prairie winters. Have tire chains in my trunk. Have used them multiple times. Only -13c this morning but was -46c a month ago. Ya. I have done the winter driving thing. I did a bit of it this morning.

My hometown used cinders. About the same as sand, but better at absorbing sunlight. No idea where they got them from.

And sand is becoming a precious resource. I believe it's been discussed on HN before.

https://www.bbc.com/future/article/20191108-why-the-world-is...

There is plenty of wind-blown sand, which I imagine is fine for this snow-on-road use. Rough river sand is getting more scarce and smooth, wind-blown desert sand should not be used for making concrete.

A lot of places are using things like beet juice in addition to sanding.

Curious would beet juice create red stains om the road?

Ive never noticed that on the roads here. You would think it would though eh, my hands are after cutting them

Could be sugar beet, which is white.

For the non-americans here americans have a very 18thC view of their own geography - the "mid-west" is not in the middle of the west

Reply on news.ycombinator.com