Our friends at Michigan State have a great site. Check out the traffic and ski "tools." For example the winter tool does:
"The tool provides information on a number of ski-relevant parameters including the number of ski days, the day of first snow, the date of last snowcover, and the amount of snow that has to be artificially generated to keep a resort open."
"Richard Medina, an assistant geography professor at the University of Utah, is studying how weather affects traffic patterns and accidents in Salt Lake County. The project could produce a model that may help emergency managers, said Medina, who previously did a similar study in the Washington, D.C., area." Listen here.