PITTSBURGH, Pa. (WPXI) — Crews continue to treat the interstates, routes, highways and other roads in western Pa. following the snowstorm and icy conditions on Christmas. PennDOT crews have been working for nearly 24 hours already, and that work is expected to continue through the early hours Saturday to make sure roadways are safe for drivers this weekend. According to PennDOT officials, this storm was a tough scenario right from the start. Rain switched to freezing rain Thursday evening, and then when wind chills plummeted even more, the snow started to fall — creating very slick conditions outside. The biggest challenge for crews has been the nonstop snowfall. Pittsburgh set a record Friday for the most snow recorded on Christmas Day with about four inches, but the White Christmas made things difficult for plows and salt trucks. All PennDOT trucks have been out treating and plowing roads, but the drifting snow and icy spots created some dangerous conditions.