Higher sun takes on an important role in melting snow and ice on highways.
It will be a race to the finish: Will solar power take care of what dwindling supplies of road salt can’t?
A warming sun might be the salvation for Washington County and city public works departments that have watched their salt reserves disappear after a winter of repeated snowstorms and unusually low temperatures.
“We’ve had a really challenging winter. We’ve had a lot of nuisance storms, back to back,” County Engineer Wayne Sandberg said. “We’re hindered here because it was so cold and the snow last time had water that caused so much ice.”
The county stockpiled 12,000 tons of salt last fall to melt ice on its 630 lane miles of road — somewhat equivalent to the driving distance from the Twin Cities to Indianapolis — but only a tenth of that salt remains. Cities in Washington County that salt their own roads have run into similar shortages, Sandberg said, and some now are using only sand in their war on ice.
“We’re down to probably about 5 percent of our annual allotment for salt, so that’s not a lot left,” said Klayton Eckles, Woodbury’s engineering and public works director. “It’s really extremely difficult to find any.”
As a result, the city was forced to dip into its salt reserves and rely more on sand, “crushed rock chips” and liquid calcium chloride to keep its streets passable after the recent heavy snowfall, he said.
“Some of things we’re adapting or changing on our local roads, the city streets, is we’re discontinuing the use of salt there completely, and we’re just using some sand at the intersections,” Eckles said. “We’re mixing our salt with a much higher percentage of sand so that it’ll go a little farther.”
Hugo public works director Scott Anderson said the city was caught off guard after this winter brought heaver-than-usual snows. He said his department took a delivery of nearly 700 tons of salt last fall, and also had a reserve of about 100 tons from the previous year.
“This year we used an unusually larger amount to try to get that ice off the road and basically used up a lot of our supply and now late in the season, with the hard winter that we’ve had and with the cold weather, we’ve had a hard time finding salt,” Anderson said. “On a normal year, we would use about 550 tons, so we always had a little bit extra, maybe 30 to 40 percent extra.”
The city’s supply has since dwindled to less than 50 tons, he said.
“I think everybody in Minnesota is in a similar situation,” said Sandberg, of Washington County.
The county bought its salt last year in a group state contract for $60 a ton. On the open market, demand has driven the price to more than $200 a ton, Sandberg said.
“We’re not going to run out of salt, but we might pay more for it,” he said.
In the most recent snowstorm, county crews applied a mix of half salt and half sand.
“It really wouldn’t be appropriate using just salt anymore with temperatures this low,” he said, because salt doesn’t melt ice in such cold weather.
That’s where the sun, ever-higher in the sky, can bring relief to public works budgets.
Because paved roads hold solar heat, less salt is needed in March than in January to achieve the same amount of melting.
In a typical snowstorm, the county puts 20 trucks to work plowing and salting. The typical big truck carries 12 tons of sand and it’s tricky, Sandberg said, to make sure it’s not wasted at the beginning of a snowstorm.