Winter's Unsung Hero

VERMONT- Winter in Vermont means cloudy days, cold and snowy weather, and winter activities such as skiing, snowboarding, and snowmobiling. Most people in Vermont prepare for the winter months by stocking up on wood for their stoves, getting winter tires, and most importantly stocking up on salt for their driveways.

 Salt is definitely winter's unsung hero. When we think of salt we think of regular table salt also known as sodium chloride or NaCl. Road salt is similar to table salt in the sense that they are both made of sodium chloride but, one difference is that road salt has added chemicals such as sodium ferrocyanide and ferric ferrocyanide which prevents caking when storing salt. 

Salt works by lowering the freezing point of water. Freshwater freezes at a temperature of 32° fahrenheit or 0° celsius, while seawater freezes at a temperature of 28° F or -2° C. The more salt you add to water the lower the temperature must be in order to freeze. However, different kinds of salt are also used on roadways and sidewalks other than sodium chloride. Magnesium chloride (MgCl2), calcium chloride (CaCl2), and potassium chloride (KCl) are also available. Magnesium chloride can melt ice up to a temperature of -5° F or -20.5° C while potassium chloride can melt ice up to a temperature of -13° F or -25° C. The most effective salt currently is calcium chloride which has a maximum melting temperature of -25° F or -31.7° C. 

 According to the Vermont Agency of Transportation (VTRANS), the most common salt used on the roadways in Vermont is sodium chloride. In order to effectively distribute the salt on the roadways, VTRANS employees will mix some of the salt with water and make a liquid and mix the liquid with the rock salt to prevents the salt from bouncing all over the place and it effectively ends up on the roadways. When temperatures dip below -15° F, VTRANS will switch from sodium chloride to magnesium chloride. The magensium chloride is made into liquid form and sprayed on the roadways and on rock salt as well. 

The state of Vermont goes through a lot of salt each year. According to VTRANS, the average amount of salt used in a year is about 175,000 tons or 350 million pounds. In comparison, an average airplane without luggage or passangers weights about 90,000 pounds that is 3,889 airplanes worth of salt a year. And this doesnt come cheap either. The annual winter maintenance budget for the 2019-2020 winter season was $36.6 million. This doesn't include the cost of a salt truck either. A 10-wheel salt truck costs $195,000 while a 6-wheel salt truck costs $170,000. Although it's a lot of driving, a salt truck driver earns $18/hr and any overtime is time-and-a-half on top of full benefits.