HANNIBAL, Mo. -- Winter Storm Decima created a snowy, icy mess for many drivers this weekend in Northeast Missouri and West-Central Illinois. Crews in both states worked overtime to clear roads for travelers.
"This weekend has gone OK," said MoDOT Hannibal spokesperson Lydia Brownell. "We had a little issue with the misty rain, but we got past it. The most trouble we had was in the south because of the rain."
Websites for the Illinois and Missouri departments of transportation said the roads with the highest volume of traffic are plowed first to a "mostly clear" status.
Then, loose top-level snow is plowed on other routes to make them passable.
The weekend's sub-zero temperatures didn't help plow crews. Chemical treatments the crews put down don't work well in extreme cold. When salt makes contact with ice, unfrozen water molecules dissolve the salt to create a saltwater solution, a science article from the National Center for Families Learning says. Salt lowers the freezing point of water, thus preventing more ice from forming.
But when temperatures drop into the low teens -- and lower -- the salt that crews put on roads isn't effective.
"Crews have been working around the clock," MoDOT Maintenance and Traffic Engineer Jennifer Hinson said. "But the ice and snow can't melt without the help of Mother Nature."