Meteorologist Dave Epstein is our go-to person for pressing weather questions on everything from winter blizzards to summer droughts. He’s also a horticulturist, meaning he’s an expert in anything that grows leaves and flowers. GBH's Morning Edition asked our audience for weather and gardening questions, and Epstein graciously answered them on the air. This transcript has been edited for clarity.
“Every day on my walk to and from the car on my way to the studio here at GBH, I've been walking on grounds that are just caked in salt, which obviously is there to prevent ice, to prevent people from slipping and buildups of snow when it's nasty outside. But now it's going to be 50 degrees. It's going to be rainy. It made me curious: Do we over salt the roads when we have just an immense buildup of it and then rain coming down?” —Jeremy Siegel, co-host, GBH’s Morning Edition
There are many things cities and towns use to prevent icy roads, Epstein said. He emphasized that he is not a member of any municipality’s Department of Public Works, nor the state’s Department of Environmental Protection.
“But some of the things some of the towns are using: Calcium chloride, magnesium chloride, or just sodium chloride, which is basically rock salt,” Epstein said. “The actual just straight salt, the rock salt, works at a temperature down to a certain amount. And then you can use calcium chloride at lower temperatures.”
When snow melts or rain comes and the salt washes off the roads, in often ends up in nearby soil, he said.
“It can harm plants and it can harm the grass strip that's near your lawn,” he said. “As a car goes by and we start to melt it, that some of that spray can get onto some of the evergreens and that can also do damage to the plants.”
There are some alternatives people can use around their homes, Epstein said, though he noted that they may not be effective, affordable, or feasible enough to use on a city- or town-wide scale.
“Sand's a great alternative in terms of traction,” he said. “I know the town of Natick allows you to get free sand and some of the towns just have it available and you can just put sand down. And if it's straight sand, there's no real environmental risk with that. It's just sand. It's going to wash away. You'll have to clean it up in the spring. But that's actually what I use, is I use a lot of sand.”
He's also looked into using products made with sugar beet juice for use around his home.
“It's a little more expensive,” Epstein said. “It's in the $60 range for a pretty big bag of it. I don't know how long it would last.”
For the time being, Epstein said, he understands why cities and towns use a heavy hand when they salt the roads.
“The alternative, of course, is that no one's going to be safe on the roadways,” he said. “It's just sort of a necessary evil to use around here in terms of those big bulk, trucks that are going by with all of that.”