Missouri's education department says the latest in a series of winter storms could cause school districts to extend classes into the summer.
Department of Elementary and Secondary Education spokeswoman Sarah Potter says public schools have already had more snow days than usual in the current academic year.
Many districts have had to call off classes the past two months because of snow, ice and cold temperatures. Potter says schools might need to cut short spring and summer vacations.
The department requires school districts to build six snow days into their calendars and those days must be made up in full. Subsequent snow days only count for a half day that must be made up during the academic year.