根据柯林斯英汉双解大词典：
N-COUNT A disaster is a very bad accident such as an earthquake or a plane crash, especially one in which a lot of people are killed. 灾难
N-COUNT If you refer to something as a disaster, you are emphasizing that you think it is extremely bad or unacceptable. 极为糟糕的事; 不能接受的事 [强调]
N-UNCOUNT Disaster is something which has very bad consequences for you. 灾祸
PHRASE If you say that something is a recipe for disaster, you mean that it is very likely to have unpleasant consequences. 祸端 [1]