I've heard the term Atmospheric River used in the US. I think it's the same thing.

Like Dan said, weather channels in the US use 'atmospheric river.' In winter, strong cold fronts from the north will be called a 'polar vortex.' I guess these terms sound more exciting.

I never heard of it before. Wikipedia has an article entitled "Flying River." It begins: "The flying river is a movement of large quantities of water vapor transported in the atmosphere from the Amazon Basin to other parts of South America."

What is the context?