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
A sudden change in weather for Europe. Thunderstorms & tornadoes. . . Thursday 2 July 2026
Split image showing a dramatic supercell thunderstorm with a lowering cloud base over farmland on the left, and a Europe lightning map on the right with dense lightning strikes and a thunderstorm warning symbol across central and southeastern Europe.
Thursday 2 July 2026

Thunderstorms & tornadoes

A sudden change in weather for Europe
June temperature record broken again. Three days running. . . Friday 26 June 2026
Temperature map of eastern England showing extreme heat around Ipswich and nearby areas, with temperatures reaching 36°C near Cambridge and a large red thermometer icon highlighting intense heat.
Friday 26 June 2026

Three days running

June temperature record broken again
June heatwave also heated up the oceans. Across Europe's waters. . . Wednesday 1 July 2026
Europe temperature map with sea temperature icons showing coastal water temperatures of 20–24°C around the British Isles, 20–25°C in the Baltic Sea, 25°C in the Black Sea, and 25–27°C across parts of the Mediterranean.
Wednesday 1 July 2026

Across Europe's waters

June heatwave also heated up the oceans
All weather news
This might also interest you
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
Seasonal warmth between spring thunder. Your weather - Your shots. . . Sunday 19 April 2026
Split image showing coastal sunset with layered lenticular clouds over rooftops and palm trees on the left, and a green valley with river and hills under soft daylight on the right.
Sunday 19 April 2026

Your weather - Your shots

Seasonal warmth between spring thunder
A frozen start to the weekend. Icy conditions. . . Friday 13 February 2026
UK temperature map dated 14.02 showing widespread subzero values in blue shading, with readings such as −4 in Glasgow, −3 in Dublin, and −2 in London, alongside a blue thermometer icon.
Friday 13 February 2026

Icy conditions

A frozen start to the weekend
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