Something seemingly appropriate for a holiday turkey clings to city streets. You may have seen its chalky deposits coating roadways before Thursday's snow.
Also known as “salt water,” brine is spread around Omaha by public works crews in advance of snowfall. At certain temperatures, officials say, brine mixes with snow and keeps it from sticking to the pavement, making it an easier target for plow blades. The city and other agencies have used it and other de-icing products for years.
But they avoid using it when it's very cold outside. If the pavement is too cold, the brine can actually cause some snow to stick.
People who pay attention to this sort of thing sometimes hear this complaint: City officials would be better off leaving the streets alone at the start of a snowfall, because pretreating pavement can create a skating rink as the brine gets diluted and the snow freezes after sticking to the ground.
“There are conditions where salt either isn't effective, or can actually create problems rather than address the slickness problem,” said Scott McIntyre, the city's street maintenance engineer and a leader of Omaha's snow removal effort. “You put that anti-icing material down there, you get some action with the vehicles, it melts right away and it's so cold it turns to ice immediately as soon as it gets diluted a little bit.”
But McIntyre said Thursday's air temperatures were around 24 degrees. Pavement temperatures were forecast to be right around freezing, McIntyre said.
Brine “should work well in those conditions,” he said.
“That's where the salt is effective in addressing the slickness.”
Less-optimal conditions for such street treatments will probably appear later this week, McIntyre said, but by then, the brined snow will already have been plowed away.
The brine solution is brewed at two city maintenance yards, according to the Public Works Department, and is sometimes mixed with sand before specially equipped trucks spread it on pavement.
This cocktail sticks to the pavement more effectively than granular salt, and the brine creates a residual caking seen on morning commutes.
Crews sometimes mix brine with a product derived from sugar beets, which officials say lowers the freezing point of normal brine and makes the solution stickier.
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