Salty solution stops sliding and snow from sticking to streets
Salt and water might just save a life, according to the Crow Wing County Highway Department. Jory Danielson is the maintenance supervisor for the department, and he said the department uses many methods to control snow and ice, so county roads ar...
Salt and water might just save a life, according to the Crow Wing County Highway Department.
Jory Danielson is the maintenance supervisor for the department, and he said the department uses many methods to control snow and ice, so county roads are safer to drive on during inclement weather, including "anti-icing."
"The biggest reason why we go out before a snow event is to get that layer of salt and water down in the strips, and the reason for the strips is that way, cars that drive over it, their tires are still making contact with the pavement," Danielson said.
Anti-icing is a process of mixing salt and water to create a brine solution, which the highway department applies to county roads in narrow line patterns while leaving small, untreated gaps between the lines.
"If we were to smear complete salt over everything, it might have a tendency to get slippery just as the snow starts to fall and the salt starts to activate. And we do it so when the snow does fall, that it does not make a complete bond with the pavement," Danielson said.
"One of the benefits of using saltwater brine is it's a lesser concentration than if we were to go out and just treat everything with regular rock salt, and it glues to the pavement, so there's less runoff."
The untreated gaps are supposed to improve a motor vehicle's traction by allowing the tires to stay in contact with the road's surface, according to Danielson, who said the department has employed the anti-icing technique since 2008.
"The quantity of salt is much less because we mix it in a liquid solution and then apply that liquid solution, and as the water evaporates out, the thin bands of salt stay on the road," Danielson said of the brine. "It's more environmentally friendly than just using straight salt on the roads."
Chlorides, sulfates, salinity, and dissolved minerals are all forms of "salts" that can harm fish and plant life at high concentrations, according to the Minnesota Pollution Control Agency.
"It can (harm) if it's overused, so that's why we are trying to use it as efficiently as possible to make the roads safe but not harm the environment," Danielson said. "We are watching that and working with the MPCA to try and be good stewards of the environment but still provide adequate road safety."
If the snowfall becomes too great for the salt to melt it, the salt creates a layer between the snow and the county roads' surface.
"When the pavement temps are warm and then cool down, all that liquid and water freezes on top and freezes in the pores of the asphalt, and then we have trouble scraping it off, so the salt kind of activates and keeps it loose, so when the plows come over, it scrapes off," he said.
The highway department used anti-icing for the first time this winter on Tuesday in preparation for Wednesday's snow. Anti-icing efforts start two to 48 hours before a snow event to allow the saltwater to dry and bond to the road, and the salt from the brine solution to melt the snow.
"We would have used it last Friday, but it was rain, and the rain would just wash it all way," Danielson said of the first snowstorm of the season in Crow Wing County.
According to the Minnesota State Patrol, there were 217 crashes-25 with injuries-and two fatal crashes in the Duluth and Brainerd areas, plus 161 vehicle spinouts on Friday.
"Friday went fairly well for us. The first snowfall is always a little bit of a dark horse that we think we've got everything in place, and we're going to prepare for the best, but something always seems to happen," Danielson said.
"However, this time, the only difficult situation for us was nothing was frozen. The shoulders of the road were still soft, so we had to be very careful going around the edges at intersections. The roads were even soft themselves, so we went with lighter loads on the trucks."
The highway department uses 17 snowplow trucks and other heavy equipment to remove snow and ice, with each of the 17 drivers assigned to a specific plow route representing "an equitable portion" of the more than 600 miles of roadway in the county.
"For the most part it was wet heavy snow," he said of Friday's snowfall. "The wet heavy snow coming off the plow tends to damage mailboxes, so we're really careful not to do that and try not to hit them with the wet heavy snow ... so that was pretty much our biggest challenge."
The highway department utilizes the anti-icing process as early and as often as possible, but it is not as effective when road temperatures fall below 15 degrees or if snow is swirling and blowing across the road.
"We have a pretty selective window we are able to use it," Danielson said of anti-icing.