Home
Weather New York
WeatherRadar
RainRadar
TemperatureRadar
WindRadar
LightningRadar
Weather News
Editor's Pick
Discover the app
Weather widget
Contact us
Apps
Career
    Home / Editor's Pick /

    What does salt do? The science of gritting

01:00 AM
January 29, 2023

What does salt do?
The science of gritting

gritter

With frost frequenting our roads amidst the cold weather, we thought it was time to take a look at what exactly gritting the roads does.

Although we often refer to it as gritting, there is usually little grit involved, and instead mined rock salt is used. Salting the roads is primarily a preventative technique, and works most effectively via three main methods:

  • Salt lowers the freezing point of water. Water freezes at 32F but the presence of the salt prevents water from freezing if it's between 17 and 21 degrees F.
  • It stops snow from bonding as ice to the road, so can be plowed away more easily.
  • Can also be added post-snow to small depths of lying snow (up to around 1.5 inches) to help dissolve and melt it away.

Salt is most commonly used because it is what we call hygroscopic. It acts like a magnet by drawing in and absorbing moisture from the air and the road surface to the granules.

If the air is too dry, or it hasn't rained recently, salt can be pre-wetted. It also needs a flow of traffic to be worked into the road properly. And if there is no moisture present, the salt won't be absorbed and thus won't do its job.

Salt can also be ineffective at particularly low temperatures. So if there is a really cold arctic outbreak, this won't work.

Other alternatives aside from salt include molasses, although depending on where you live, can often get licked up by sheep, which is a road hazard in itself!

Weather & Radar USA editorial team
More on the topic
Heat wave setting records across Europe. London breaks May record. . . Tuesday, May 26, 2026
European heat wave
Tuesday, May 26, 2026

London breaks May record

Heat wave setting records across Europe
Heat is affecting agriculture globally. WMO report. . . Sunday, April 26, 2026
A young woman is kneeling in a cornfield, tending to her plants
Sunday, April 26, 2026

WMO report

Heat is affecting agriculture globally
Longest day of the year is here. Summer solstice. . . Sunday, June 21, 2026
Sunday, June 21, 2026

Summer solstice

Longest day of the year is here
All weather news
This might also interest you
Extreme heat for 100 million people. 14 years last 100 degrees. . . Monday, June 29, 2026
Monday, June 29, 2026

14 years last 100 degrees

Extreme heat for 100 million people
Ring of fire developing. Storms encircle heat. . . Wednesday, July 1, 2026
Wednesday, July 1, 2026

Storms encircle heat

Ring of fire developing
Watch the heatwave build. Record-breaking heat. . . Monday, June 29, 2026
Monday, June 29, 2026

Record-breaking heat

Watch the heatwave build
All articles
Weather & Radar

Weather & Radar is also available on

Google Play StoreApp Store

Company

Contact us Privacy policy Legal info Accessibility statement

Services

Uploader

Socials

instagramfacebookthreadslinkList