Home
Weather Dublin
WeatherRadar
RainfallRadar
TemperatureRadar
WindRadar
LightningRadar
Weather News
Editor's Pick
Discover the app
Weather widget
Contact us
Apps
    Home / Editor's Pick /

    What does salt do? The science of gritting

09:00
23 December 2022

What does salt do?
The science of gritting

gritter

Contrary to popular belief, salt does not stop snow from settling, so what exactly does it do?

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 0C but the presence of the salt prevents water from freezing until -6C to -8C.
  • It stops snow bonding as ice to the road, so can be ploughed away more easily.
  • Can also be added post-snow to small depths of lying snow (up to around 4cm) 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.

Salt can also be ineffective at particularly low temperatures, so if you live somewhere like the Scottish Highlands, then it's likely that a mix of salt and grit will be used.

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!

Each year new names are unveiled for council's gritter lorries, with this year featuring David Plowie, Salt Disney, Sled Zeppelin and Sleetwood Mac.

Weather & Radar editorial team

More on the topic

Heavy rain again in the south of France. Another bout of disruption. . . Wednesday 4 November 2026
Split image showing heavy rain and lightning near Montpellier, Marseille and Monaco on a weather map, alongside cars stranded on a flooded road.
Wednesday 4 November 2026

Another bout of disruption

Heavy rain again in the south of France
Frosty nights on the horizon in Europe. Cold autumn air. . Weather Videos. Tuesday 3 November 2026
Temperature forecast for Friday in Central Europe. The blue areas indicate freezing temperatures, particularly from eastern Germany through the Czech Republic to Austria.
Weather VideosTuesday 3 November 2026

Cold autumn air

Frosty nights on the horizon in Europe
Autumn is the season for fog. High pressure, but no sun. . . Thursday 5 November 2026
A split-screen image showing the weather radar for Europe and a mountain landscape. On the right, snow-capped peaks rise above a thick blanket of fog against a blue sky.
Thursday 5 November 2026

High pressure, but no sun

Autumn is the season for fog
All weather news

This might also interest you

Bright and warm conditions take hold. Spring-like outlook. . . Thursday 23 April 2026
Split UK map showing warm temperatures up to 21 degrees in orange on the left and clear sunny conditions with temperatures from 12 to 18 degrees on the right, with sun icons across the country.
Thursday 23 April 2026

Spring-like outlook

Bright and warm conditions take hold
A stormy week in the skies above. Your weather - Your shots. . . Sunday 30 August 2026
Split image showing lightning branching beneath dark storm clouds above rooftops on the left and an orange-pink sunset over a calm sea on the right.
Sunday 30 August 2026

Your weather - Your shots

A stormy week in the skies above
Historic Storm Éowyn arrives. On this day.... . . Saturday 24 January 2026
Split image showing a person in a yellow jacket struggling against strong winds and heavy rain on a street at night on the left, and an Irish wind forecast map on the right with red and purple shading, gusts up to 75 mph, and a wind warning icon, divided by a curved white line.
Saturday 24 January 2026

On this day...

Historic Storm Éowyn arrives
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

facebooktwitteryouTubelinkList