Salting roads before the arrival of snow is pointless!

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

Before talking about salting, a little physics lesson is in order. 0 degrees is the equilibrium point between liquid water and ice. A little colder, water turns into ice. A little warmer, ice turns into water. By adding salt to water, you 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 roadway.

Salting the roads is therefore the most commonly used solution to allow vehicles to circulate without problems. We are not talking about 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, has been forecast for several days, so we can think that public services had plenty of time to spread a generous layer of salt on the asphalt. Well no, and fortunately, as it would have been useless!

Salting at the right time

For this technique to be effective, it is essential not to salt too early, long before the cold and snow arrive. Salt would anyway be washed away from the roads by the passing cars. It is preferable to do the initial salting just after the freezing point, that is, when temperatures drop and cause the formation of flakes. In summary, salting should start when it begins 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 replaced, its salt content decreases.

Finally, it must be kept in mind that nature is more powerful than man and all his technologies. The use of winter tires in winter is mandatory in certain regions but is not required throughout the 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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