Home
Weather London
WeatherRadar
RainfallRadar
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

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
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
Turbulent times as gusting winds spread. Scotland affected too. . . Tuesday, 30 June 2026
WindRadar over the Mediterranean, showing the Mistral in the west and the Bora in the east. Strong winds and high wind speeds along the French Mediterranean coast and the Adriatic coast.
Tuesday, 30 June 2026

Scotland affected too

Turbulent times as gusting winds spread
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
New records for England and Wales. Broken again tomorrow?. . . Thursday, 25 June 2026
Temperature map of southwest Britain on 25.06 showing extreme heat across southern Wales and southwest England, with Bute Park in Cardiff highlighted at 34.2°C and Yeovilton at 36.4°C amid widespread deep red heat zones.
Thursday, 25 June 2026

Broken again tomorrow?

New records for England and Wales
Turbulent weather in the Canary Islands. Storm and rain. . . Friday, 12 December 2025
Weather graphic showing rain and wind fields over the Canary Islands and a central warning symbol.
Friday, 12 December 2025

Storm and rain

Turbulent weather in the Canary Islands
Flooding, gales, and heavy snow. Storm Chandra. . . Tuesday, 27 January 2026
Split image showing aerial flooding in a town with muddy water covering roads on the left, and a rural road on the right blocked by heavy snowfall with vans stopped and a person walking in snow.
Tuesday, 27 January 2026

Storm Chandra

Flooding, gales, and heavy snow
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

facebooktwittertikToklinkList