FORT WAYNE, Ind. (WANE) — After the last few days of snow, salt and other alternatives have been instrumental in helping to clear roadways and sidewalks. However, if you are just using salt it’s important to be aware of how much the effectiveness drops when bitter cold arrives.
When a salt solution is used as a pretreatment on roads, it helps to lower the freezing point to slow the ability of water to form solid ice crystals. Once the snow is on the ground, any salt that is dumped on top of the ice relies on the sun or friction of car tires driving over it to initially melt the ice into slush. Once the liquid and salt are mixed, it behaves just like the solution to prevent refreezing of the roads.
However, salt is only effective above certain temperatures.
In the chart above you can see that salt is very effective when the temperature is 30 degrees, one pound of salt will melt 46 pounds of ice. That efficiency changes rapidly as the temperature drops, by the time the temperature is 20 degrees only 9 pounds of ice are melted by one pound of salt.
During the day salt has the assistance of sunshine to aid in the melting process, but if the temperatures drop back below 15 degrees the melted snow can refreeze into ice.
Magnesium chloride offers a great alternative to salt as it is effective in temperatures near 20 below zero, while also being more environmentally friendly. Salt can damage the environment in the long term, in addition to being harmful to pets and plants. A drawback to magnesium chloride is that it costs several times that of salt. Sand is also an alternative, however, it is not for melting, rather it helps cars have a better grip on the roads.
Always make sure to be aware of your surroundings both on the roads and on sidewalks when the bitter cold arrives after a recent snowfall.