1. unexpected
2. unannounced, unheralded, unpredicted, unanticipated, unforeseen, unlooked-for, out of the blue, unhoped, unhoped-for, unthought, unthought-of, unprovided for, upset, surprising, unsuspected
3. forced
4. unscheduled, surprising
5. unplanned
6. unforeseen
6. sudden