It is not reasonable to expect students to reschedule flights (probably booked full anyway and VERY expensive to change last minute) to get back earlier than planned from a break. Not everyone drives back to campus from holiday and can just adjust to the forecast with a weeks notice. That said I don’t think it’s necessary to cancel classes (unless the faculty also can’t make it back, which should be a concern as well.) Just hold class but make it a “special topic” discussion or study day-- not one that is urgent to make up and no penalty for missing.