Salting roads before the arrival of snow is pointless!

First snowy episode of the year and the first controversies arise regarding the right time to salt the roads.

Before discussing salting, a little physics lesson is in order. 0 degrees is the equilibrium point between liquid water and ice. A bit colder, water turns into ice. A bit warmer, ice turns into water. By adding salt to water, we alter this equilibrium point down to -10 degrees, thus preventing water from freezing, or in the case we are interested in, melting ice despite negative temperatures, and especially preventing it from accumulating and creating a slippery layer on the road.

Road salting is therefore the most commonly used solution to allow vehicles to circulate without issues. It is not pure salt, but brine, a mixture of sodium chloride, calcium, and magnesium, to which a bit of sand is often added to improve tire grip. The snow arriving from the North on Thursday, November 21, which now covers Île-de-France, had been forecasted for several days, so one might think that public services had ample time to pour a generous layer of salt on the asphalt. Well no, and fortunately because it would have served no purpose!

Salting at the right time

For this technique to be effective, it is essential not to apply salt too long before the arrival of cold and snow. The salt would be washed away from the roads by passing vehicles anyway. It is preferable to start salting just after the freezing point, that is, when temperatures drop and flakes start to form. In summary, salting should begin when it starts to snow. This prevents the snow from creating a film that sticks to the ground. Secondly, the effect of salt is temporary and requires regular renewal, as the ice melts and is replenished, its salt content decreases.

Finally, it should be kept in mind that nature is more powerful than man and all his technologies. Using snow tires in winter is mandatory in some areas but not across the entire territory, unlike many northern countries that logically have fewer traffic problems than we do despite much more snowfall. However, the best way to combat snow on the road is still not to take the road when it snows. Snow and ice: how to drive safely?

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