impending catastrophe / looming catastrophe

Hello everyone,

I came across the two phrases “impending catastrophe” and “looming catastrophe” today, in the below contexts respectively, which made me start to think if the two phrases are interchangeable.

Then came an ultimatum from Austria-Hungary to Serbia, practically indicting the Serbian nation for complicity in the murder, making demands which could be acceded to only by compromising Serbian honor and independence, and requiring an answer within forty-eight hours, This imperilled Russian interests in the Near East, and threatened to involve the Triple Entente in war with the Triple Alliance. For two weeks Sir Edward Grey and other statesmen made frantic but vain efforts to ward off the impending catastrophe. Soon Europe was resounding to the tread of countless hosts. The World War had begun. (Source: The American People: A History. Written by Thomas Jefferson Wertenbaker.)

Now, more than ever we need discipline and self-discipline, civil conciliation, hard and selfless labor, and confidence in our own forces. We must not give up ourselves or frighten people with a looming catastrophe. The entire society, all work collectives and every individual, must proceed from words to deeds and decisively move forward. (Source: Excerpts Gorbachev Speech to Congress. Translated by the Associated Press.)

The nuance seems to be: “impending catastrophe” carries the connotation that the catastrophe is about to happen and it is inevitable, whereas “looming catastrophe” only suggests that the catastrophe is (perceived to be) threatening. Am I correct on this? Hope someone could offer me some opinion(s).

Thanks.