A ferry company serving Yakushima offers a real-time status/schedule page with this handy key:
○：通常運航 △：条件付運航 ※：状況待ち 欠：欠航
The first and the last are clear enough (normal operation and cancelled, respectively), but the two in the middle literally translate to "conditional operation" and "waiting for situation". What do these mean in practice?
In their FAQ, the airline Skymark suggests 「条件付き運航」 means "will try to operate, but may divert or cancel if the weather gets worse". 「状況待ち」 doesn't have much in the way of relevant hits, but I'd guess it means they haven't made the call on whether to run or cancel yet?