Officials at Flagstaff Unified School District decided Monday afternoon to cancel classes for Tuesday. Also canceling school Tuesday are Northland Prep Academy, Flagstaff Arts and Leadership Academy and others. Williams schools are also taking a snow day as well. The decision comes because of a strong winter storm that is expected to affect Flagstaff and surrounding areas Tuesday into early Wednesday. The National Weather Service is calling for nine-to-13 inches of snow in Flagstaff and six-to-ten inches in Doney Park between Tuesday and Wednesday.