The unusual variety of weather this season has made it difficult to keep the roadways clear of ice and snow,according to St. Croix County Highway Commissioner Tim Ramberg.
One of the most difficult weather conditions to deal with, Ramberg said, is freezing rain.
"You can't really plow ice," Ramberg said. He said it needs to be melted off with material like road salt. However, he also said road salt stops working at about 15 or 20 degrees Fahrenheit, which means the highway department has to mix in additives to enable the salt to effectively melt the ice.
But what Ramberg said is hardest to deal with is not ice on its own, but rather the assortment of weather conditions dealt out in quick succession by the recent unusual weather. Ramberg said even within one storm, the conditions can change from one area of the county to the next.
"Within a mile you can have quite a variety of different types of material going down," Ramberg said. "That makes a mess because you get your truck loaded up with one type of material and then you have a different type of condensation out there."
Ramberg said the highway department has several salt additives they turn to in various weather conditions. These include several types of chloride, sand and an organic road salt additive called GEOMELT 55 Organic Deicer, which highway department workers have nicknamed "beet juice."
The different additives are effective at different temperatures, Ramberg said.
He said weather can change how effective road salt and its additives are as well.
Sunlight helps melt the ice from the roadway. Ramberg said the highway department has software that helps predict when the sun will come out. The highway department uses these predictions to salt the road before the sun comes out, but Ramberg said the predictions aren't always accurate.
"We can plan on one thing and then the sun doesn't come out, so that makes it different," Ramberg said. "The travelling public is pleasantly surprised when we get the timing right."
Ramberg said varying road conditions can determine whether or not snow or ice will "bond" or stick to the surface of a road. These variables can include temperature, wind speed and dew point.
"You get some wet conditions, the dew point moves on you, you get black ice," Ramberg said.
Ramberg said the highway department has locations strategically located throughout the county so as to be able to respond quickly when a storm hits. But, depending on the storm, it just takes time to get roads fully cleared.
"Our hope is that within three hours, we drive by your house and punch a hole through the main roads," Ramberg said. The goal is to have roads usable as soon as possible and completely cleared within three days of the storm. He said this can be complicated by snow melting during the day, then refreezing into ice at night when the temperatures drop.
Ramberg said during a storm the plows drive thousands of miles to clear the snow.
"That's the equivalent of driving to El Paso, Texas and back," Ramberg said, and that is on one pass alone. It takes multiple passes to get roads fully cleared, he said. That is one reason Ramberg said it can take more than one day to clear the roads after a storm.
Ramberg said the highway department also has measures in place to prevent roads from becoming icy or to mitigate road conditions.
Given enough warning, Ramberg said the highway department can put down ice-melting chemicals before a storm hits to prevent ice and snow from sticking to the ground.
"That hasn't been as effective for us as some places," Ramberg said. Especially, he added, as storms have not been happening as predicted lately.
Ramberg said the highway department also has to clear roads in a specific order, beginning with those most travelled, like Interstate 94, and ending with the smallest county-maintained roads. Town and city roads are typically maintained by the municipality to which they belong.
The set priority for clearing roads, Ramberg said, is another reason it may take the highway department longer to clear all the county's roads.
"I'd just like to thank the public for all their patience in all these events," Ramberg said. "They've been very patient."