Just how effective is salt at melting ice on roads in below-freezing temperatures?

Road salt helped keep Wednesday morning’s commute smooth

DETROIT – A lot of salt was applied to Metro Detroit roads Wednesday morning and it worked effectively to keep the commute smooth for many drivers.

Temperatures Wednesday morning played a big role in why salt worked so effectively. So, how effective is salt when the temperatures drop?

A single pound of salt will melt 46 pounds of ice when temperatures are 30 degrees or above. The effectiveness of salt starts diminishing rapidly as the temperature gets colder.

If temperatures get down below 15 degrees at night the salt works so slowly that it is basically ineffective. During the daytime, salt will still work because solar radiation gets through even if there are clouds. It may work a little slower than usual, but it will still work.

Read: Road salt is bad for the environment: What are some alternatives?

TemperaturePounds of ice melted by 1 pound of salt
30 degrees46 pounds of ice
25 degrees14 pounds of ice
20 degrees9 pounds of ice
15 degrees6 pounds of ice
10 degrees5 pounds of ice
5 degrees4 pounds of ice
0 degrees4 pounds of ice

Read more: When does salt work, and when does it not?


About the Authors:

Local 4 meteorologist Paul Gross was born in Detroit and has spent his entire life and career right here in southeast Michigan. Paul has researched, written and produced eight half-hour documentaries for WDIV, as well as many science, historical and environmental stories.

Kayla is a Web Producer for ClickOnDetroit. Before she joined the team in 2018 she worked at WILX in Lansing as a digital producer.