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Posted at 4:00 AM ET, 01/28/2009

Deicer Dilemma: How to Choose and How to Use

By Ann Posegate

Wx and the City

* Our Latest Forecast: Showers Then Overnight Refreeze *

An icy walkway. By David Stonner. Courtesy FEMA.

Many Washington-area residents have been applying deicing products over sidewalks and driveways last night and this morning. This is an important precaution to take to avoid accidents and injury. However, there are many products to choose from, and safe and effective ways of applying them. Here are some tips for choosing deicers and reducing environmental impact.

Experts recommend choosing calcium chloride over rock salt (sodium chloride). Calcium chloride costs more, but lasts longer -- it can be used in smaller amounts than rock salt. Also, it does not contain cyanide, an anti-caking chemical that can harm aquatic life. Calcium chloride is effective to about minus 25 degrees Fahrenheit; rock salt is effective to about 10-15 degrees Fahrenheit. Calcium Magnesium Acetate (CMA) is the safest choice overall, but costs much more.

Keep reading for more on choosing a deicer and usage tips...

Check out page 3 of this document (PDF) from the Center for Watershed Protection for an analysis of common deicers, their costs and their effects on the Chesapeake Bay watershed.

All road salts and sand can have a negative impact on the local environment by infiltrating into groundwater supplies, washing into nearby rivers and streams or harming vegetation. To reduce the impact, here are some tips to remember:

Before you apply a deicer, remove as much snow and ice as possible. Deicing products are most effective when they are applied to a thin layer of ice.

Apply early. Deicers are most effective and last the longest when applied before accumulation starts. (Remember this for the next storm.)

Follow directions carefully, and only apply as much as you need. A little goes a long way. About one handful of rock salt per square yard will do the trick; one handful of calcium chloride will treat about three square yards. Adding extra product won't speed up deicing.

Know your landscape. Road salts can harm trees and other woody plants that are intolerant to salts. If you use a deicer at home, leave a safe space around sensitive species (check out page 4 for a list of sensitive species).

Thanks to Earth Gauge for these tips.

By Ann Posegate  | January 28, 2009; 4:00 AM ET
Categories:  Posegate, Winter Storms, Wx and the City  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   StumbleUpon   Technorati   Google Buzz   Previous: Ice Sets Stage for Sloppy AM Commute
Next: Forecast: Struggling Toward 32°, Refreeze Tonight


Pretreating the driveway . . . For The Win!

Posted by: ah___ | January 28, 2009 8:31 AM | Report abuse

Thank you for posting this!

Posted by: rallycap | January 28, 2009 9:23 AM | Report abuse

The photo of the woman pouring water on her windshield is a perfect example of what NOT to do. She is asking to have it shatter. Warm up the car and scrape.

Posted by: jackdmom | January 28, 2009 9:32 AM | Report abuse

With a little thing called EFFORT, you usually don't need the stuff. Especially when it will melt later the same day ... I've had the same bag of rock salt for 20 years.

Posted by: upland_bill | January 28, 2009 9:34 AM | Report abuse

Great information, Ann. It's something we all should take very seriously.

I believe most, if not all, local governments are using calcium chloride. However, I question whether the amounts dumped on streets and highways are not overkill. While driving yesterday behind more than one salt truck, the amount being dumped was so thick it appeared I'd be driving on snow/slush rather than just a thick layer of salt on otherwise just wet pavement.

Posted by: SteveT-CapitalWeatherGang | January 28, 2009 9:38 AM | Report abuse

I also laughed at the woman using hot water on her windshield. Excellent way to get it to crack. My solution to scraping a car was to cover my windshield and front side windows with an old, blue, nylon tarp. This morning I just pulled it off and my windshield and windows were clean. Heater on full and rear window defrost had the rest of the windows easy to scrape by the time I got to my carpool buddy's house a mile away.

And for those people scared of slipping: find an old pair of running shoes in your closet, go to the local hardware store and buy short machine screws, and then screw a few into the chunky part of the shoe sole. You have cheap, and easy no slip ice shoes.

Posted by: JorgeGortex | January 28, 2009 10:07 AM | Report abuse

Also look into a product called Yak Trax (or something like that). They slip on over your shoes--they're basically rubber and metal coils and really help in ice.

Posted by: ah___ | January 28, 2009 10:26 AM | Report abuse

Having moved to D.C. years ago from New England, I am still amazed at the conditions on side roads and walkways during winter storms here. It seems the main roads are always over-treated with salt (not good for local water quality), and the side roads and sidewalks are under-treated, if at all. It's District law that property owners clear snow and ice from their walkways within 8 daylight hours of snow, sleet, or ice. Given that many people in this city walk to work or Metro, this could be better enforced.

Steve, I think D.C. uses a mixture of calcium chloride and rock salt. Not sure about MD or VA. Virginia has started pre-treating their roads - a method that works well in northern states. Here is DDOT/DDPW's plan for salting yesterday...a lot of resources go into trying to keep our roadways safe.

How were MD and VA roads this morning?

Posted by: Ann-CapitalWeatherGang | January 28, 2009 10:46 AM | Report abuse

JorgeGortex, remember that you not only need to clear snow and ice from your windows, but from your whole car. It's great that you can see, but you also need to make sure there aren't chunks of frozen precipitation that will fall off of your car as you drive. You can cause severe injury to others if a big chunk of snow or ice falls onto the roadway or another vehicle. In many places, it's the law.

Posted by: nashpaul | January 28, 2009 11:10 AM | Report abuse


You're welcome! Glad you found it useful. Let us know how the deicing goes...

Posted by: Ann-CapitalWeatherGang | January 28, 2009 11:39 AM | Report abuse

ann, et. al, a few years ago, we went to the local hardware store to get something for our icy sidewalk. the store clerk suggested ammonia pellets, since it functioned similar to rock salt but then could be fertilizer for the grass, too. now i know that excess fertilizer is bad for the chesapeake bay! so CaCl it is - thanks for the info. :)

Posted by: grace515 | January 28, 2009 11:46 AM | Report abuse

@nashpaul: I wouldn't leave large chunks of ice or snow on the car. A film, yes. There is no way to get that off without killing the finish. Then again, a larger tarp would take care of that whole issue.

@Ah__: I have Yak Trax as well and used them this morning. Worked nicely. I suspect in super smooth ice they'd be less effective and my DIY solution more so. Also cheaper.

@Ann-CWG: I would have to say- have fun with my ice and snow side walks. Those laws are nice unless you are a senior citizen, have a bad back/kneed/shoulder, etc. Yes, people should try to clear off such pathways but practicality speaks larger volumes to me. Besides, for me, most days this time of year I leave about dawn and come home after dark. Its a long day and I am not going to go out and kill myself shoveling or chipping for hours. People need to take some additional personal responsibility for their safety and travel. Let people help as they can. ps- I didn't have side walks until a year ago. Didn't ask for them. County put them in. Why are they now my responsibility? Let the dogooder who campaigned for their installation come over and handle it.

Posted by: JorgeGortex | January 28, 2009 12:41 PM | Report abuse

nash, good point. that should be the law here too.

Posted by: dealer1 | January 28, 2009 12:44 PM | Report abuse

Also note that some deicers will eat away at concrete and masonry.

Posted by: Corn_Laden | January 28, 2009 1:09 PM | Report abuse


Good point. There are definitely instances when shoveling and de-icing are not safe or convenient. One simple solution is to salt before the storm even hits - less time, less salt, more efficient and safer.

I am most concerned with icy sidewalks on main roads and in front of public buildings, storefronts and apartments, where there is the most foot traffic.

Posted by: Ann-CapitalWeatherGang | January 28, 2009 1:34 PM | Report abuse

Calcium chloride can cause substantial pitting and pock marks in your beautiful concrete driveway, especially if the concrete is less than 10-years old, and the snow does not evaporate, causing thaw and re-freeze cycles. The bags of calcium chloride will absorb moisture and turn to bags of water if left in a garage for more than a season.

Posted by: uncledak | January 28, 2009 2:06 PM | Report abuse

Please explain to your readers that salts, either sodium chloride or calcium chloride, do not melt ice! They merely lower the freezing point when they are dissolved in water. Let's stop perpetuating this misinformation.

Posted by: eurocentric_allen | January 28, 2009 2:17 PM | Report abuse

Thank you for discussing this. In front of most business the sidewalk is cleared, but not in front of homes. That can make walking very treacherous for everyone. Please, if you have a sidewalk in front of your home take a few minutes to shovel or de-ice. If you have an elderly neighbor or someone else who can't do it themselves -- or a vacant home -- please do in front of that home too. Those terrified of falling and injuring themselves will bless you.

Posted by: epjd | January 28, 2009 2:37 PM | Report abuse

euro_allen: what would you rename it? "Ice-freezing-point-lowering pellets"? When used ice turns to water, or melts. The fact that it's because the water's freezing point is lowered, rather than the ice's actual temperature is increasing, is rather immaterial.

Posted by: ah___ | January 28, 2009 2:57 PM | Report abuse

Euro is incorrect. Salts don't raise the temperature of ice, but melt it by changing the freezing point. The conversion of the solid phase to the liquid phase is, by definition, melting. Or, as the old saying goes, there's more than one way to skin a cat.


Posted by: FairlingtonBlade | January 28, 2009 3:08 PM | Report abuse

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