Comments on: Why does my street look white?

Question: Why does my street look white?

padjet1 — Mon, 22 Jan 2007 18:14:04 -0800

Why do roads take on a whitish-grey color in winter? And I don't mean because of snowfall.

I grew up in warmer climates. But in my time in the northeast, I've noticed that, during the winter, city roads turn white in places when there is no snow accumulation, and I've long wondered why. Is it due to moisture (or lack thereof)? A chemical reaction? An optical illusion?

By: true

true — Mon, 22 Jan 2007 18:16:20 -0800

Perhaps salt from the roads when it snows, crushed and spread out by all the traffic?

By: brianogilvie

brianogilvie — Mon, 22 Jan 2007 18:17:19 -0800

It's road salt. It dissolves in snow or rain, then precipitates in a fine white film as the water evaporates.

By: orangemiles

orangemiles — Mon, 22 Jan 2007 18:18:16 -0800

Salt. If your city's department of transportation is doing its job, they'll have the salt trucks out spreading salt at the first sign of frost. That lowers the freezing point of water, keeping the roads ice-free. You'll notice the salt buildup on your shoes, on cars, etc.

By: The God Complex

The God Complex — Mon, 22 Jan 2007 18:20:06 -0800

I really wanted to answer this question, but everyone else did =/

Salt, dammit. Salt.

By: Kraftmatic Adjustable Cheese

Kraftmatic Adjustable Cheese — Mon, 22 Jan 2007 18:21:19 -0800

I understand that it might have something to do with salt.

By: padjet1

padjet1 — Mon, 22 Jan 2007 18:23:20 -0800

How can it be salt when there's been no appreciable snowfall so far this year? I live in NYC.

By: Civil_Disobedient

Civil_Disobedient — Mon, 22 Jan 2007 18:25:52 -0800

Because people bought a shitload of salt for fear of upcoming storms, which, though never materialized, give everyone a great reason to spread the stuff whenever the lightest flurry passes through.

By: The God Complex

The God Complex — Mon, 22 Jan 2007 18:26:18 -0800

The salt isn't in the snow. The salt is something the city puts down on the streets/sidewalks, usually before a big freeze, in ordre to keep the roads safe. So if, for example, meteorologists are predicting sub-zero temperatures, the city puts salt down everywhere in order to keep ice from forming.

By: Verdandi

Verdandi — Mon, 22 Jan 2007 18:26:46 -0800

Lick the ground. That'll let you know whether or not it's salt.

Seriously, though: no appreciable snowfall? Maybe it's the whole "Western New York lake-effect snow" thing, but we've gotten a bunch.

By: sonofslim

sonofslim — Mon, 22 Jan 2007 18:27:08 -0800

Doesn't have to be snowy before they salt the streets, just cold enough to freeze. Also, salt salt salt salt salt.

By: padjet1

padjet1 — Mon, 22 Jan 2007 18:35:13 -0800

The salt isn't in the snow.

Fortunately, I'm not quite that dense. That would be a cool thing though -- self-melting snow.

I guess it hadn't occurred to me that people are so trigger-happy with the ground salting absent precipitation. I was secretly hoping for a more exotic explanation.

By: Dipsomaniac

Dipsomaniac — Mon, 22 Jan 2007 18:41:39 -0800

Well, the city will spread salt if it's raining and the forecast says that it might get below freezing. That explains why they've been using it.

By: The God Complex

The God Complex — Mon, 22 Jan 2007 18:57:09 -0800

Sorry, I mean the salt isn't in the snow in the sense that they don't usually wait for the snow to be on the ground before they salt (which would lead to horrific road conditions). Generally it's pre-emptive. Or, if you live on the west coast of Canada, it's assuredly not pre-emptive. In fact, six inches of snow will shut down major cities for one, two, even three days, given the poor anti-snow assault teams ;)

By: Krrrlson

Krrrlson — Mon, 22 Jan 2007 19:09:03 -0800

The answer is salt. Can't believe no one got that.

By: raconteur

raconteur — Mon, 22 Jan 2007 21:17:31 -0800

You guys are all wrong. The answer is salt.

By: donpardo

donpardo — Tue, 23 Jan 2007 04:12:44 -0800

NaCl.

By: Cat Pie Hurts

Cat Pie Hurts — Tue, 23 Jan 2007 07:28:52 -0800

"That would be a cool thing though -- self-melting snow."
umm...

By: drezdn

drezdn — Tue, 23 Jan 2007 09:56:05 -0800

I'm going to go against the grain here, and say that salt is only part of it. In my experience in Wisconsin, in the winter, it seems we get very few non-cloudy days. The lack of direct sun light seems to cast a grayish pall over everything, especially making the streets and anything concrete look exceptionally drab. I know for a fact that it looked like this, this year before we had any snow.

By: flabdablet

flabdablet — Tue, 23 Jan 2007 14:14:31 -0800

That, and maybe salt.

By: PetiePal

PetiePal — Thu, 25 Jan 2007 09:35:27 -0800

Road salt and gravel/rock. These get spread even when it MIGHT be icy, especially in NYC.