Winter weather can bring snow, sleet, freezing rain, and ice to your doorstep. When this winter weather strikes, it's important to know what your responsibilities are to help keep your neighborhoods safe in the aftermath. City, county, and state governments are typically responsible for keeping public roads clear and safe during these winter weather events, but if you live in a private home (even as a renter) you’re probably responsible for clearing ice and snow from your driveway, the area around your mailbox, and the sidewalk adjacent to your home. Are you prepared for the job and up to speed on your winter salt smarts?
How does salt melt ice?
After you shovel, different salt compounds (also called deicers) can help keep these areas clear by lowering the freezing point of the precipitation when it hits the ground. When the salt’s individual chemical components mix with the wintery precipitation, they can interfere with the water’s ability to form a solid, or freeze. This can melt existing snow or ice already on the ground, and help to reduce the amount of ice and snow that will accumulate after the salt is applied. The application of the salt doesn’t completely prevent the water from freezing, it just pushes the freezing temperature of the water from 32°F to a lower temperature, which varies with the type of salt used. If you are looking to use salt to help with ice removal around your home or vehicle, check the temperature range on the packaging—areas that experience more extreme cold will require different salts than areas that have a more temperate climate.
Negative impacts of salt
While salts can help make sure that your pathways stay safely clear of ice and snow, too much salt can have negative repercussions on aquatic organisms, such as coral reefs, as well as on the nation's supply of drinking water when the snows melt and carry away the deicers into local waterways. A recent study from the Proceedings of the National Academy of Sciences shows that the salinity (or salt content) of US rivers and streams has increased over the past 50 years, with 37% of the drainage area of the contiguous United States seeing an increase in salinity, posing a serious threat to drinking water, natural ecosystems, and urban infrastructure. While road salt is not the only contributing source to this increasing salinity, it is a major factor.
To cut down on over-using deicers, be sure to follow the instructions on the salt packaging, using the deicers sparingly, and keeping them away from plant life. EPA has a list of deicers that qualify to carry the Safer Choice label, a label that EPA gives to chemical products that have ingredients that are safer for humans and the environment, without sacrificing quality or performance. Check out the list of Safer Choice qualified deicers here: https://www.epa.gov/saferchoice/products (Select “deicer” under the Product Type (Optional) drop-down menu.)
Sources:
- City of Chicago. 2015. “Sidewalk Snow Removal.” Accessed November 30. http://www.cityofchicago.org/city/en/depts/cdot/supp_info/sidewalk_snow_removal.html
- City of Newark. 2014. “Snow Removal Guide.” Newark: City of Newark. http://www.ci.newark.nj.us/wp-content/uploads/2014/12/Snow_Removal_2014.pdf
- County of Dane. n.d. “Save Money—Use Less Salt This Winter.” County of Dane. https://pdf.countyofdane.com/myfairlakes/11Nov_low_salt_usage.pdf
- Dennis, Brady. 2017. "The Nation's Rivers and Streams are Getting Dangerously Saltier." The Washington Post, January 8. https://www.washingtonpost.com/news/energy-environment/wp/2018/01/08/the-nations-rivers-and-streams-are-getting-dangerously-saltier/
- Draper City. 2014. “Draper City Snow Removal Information – Winter 2014.” Draper: Draper City. http://www.draper.ut.us/DocumentCenter/View/230
- “How Minnesotans Clear the Streets in Winter: An Exercise in Freezing Point Depression.” n.d. University of Minnesota. http://www.chem.umn.edu/groups/penn/Exp10.pdf
- Kimbrough, Doris R. 2006. “Salting Roads: The Solution for Winter Driving.” ChemMatters, February. 14-16. http://www.acs.org/content/dam/acsorg/education/resources/highschool/chemmatters/articlesbytopic/solutions/chemmatters-feb2006-salting-roads.pdf
- National Science Foundation. 2018. "Winter Road Salt, Fertilizers Turning North American Waterways Increasingly Saltier." [Press Release]. https://www.nsf.gov/news/news_summ.jsp?org=NSF&cntn_id=244099&preview=false
- Samenow, Jason. 2018. "'Bomb Cyclone' Blasting East Coast Before Polar Vortex Uncorks Trememndous Cold Late This Week." The Washington Post, January 3. https://www.washingtonpost.com/news/capital-weather-gang/wp/2018/01/02/monster-storm-to-blast-east-coast-before-polar-vortex-uncorks-tremendous-cold-late-this-week/
- Samenow, Jason. 2018. "The 'Bomb Cyclone' by the Numbers: Here's How Much Snow, Wind and Flooding it Unleashed." The Washington Post, January 5. https://www.washingtonpost.com/news/capital-weather-gang/wp/2018/01/05/the-bomb-cyclone-by-the-numbers-heres-how-much-snow-wind-and-flooding-it-unleashed/?utm_term=.eee2bddfdf3c
