Snowfall snarled traffic on central Indiana highways Thursday morning as police reported numerous crashes. Dozens of school districts across the state canceled classes as the National Weather Service issuing winter storm warnings or advisories for the entire state. Snow is expected to continue throughout the day. State police say a semitrailer driver was critically injured in a crash on northbound Interstate 65 near Columbus. Police also closed sections of I-65 near Franklin and Lebanon and I-70 near Greenfield at times because of crashes and slide-offs. Numerous slide-offs also were reported on I-69 near Anderson. A driver was reported killed in a crash with a school bus on U.S. 231 near Delphi. Fox59 will have more at 4 p.m.