is "the rain fell in a curatian across the landscape" a metaphor?

Answer 1

Do you mean, "the rain fell in a curtain across the landscape"? If so, yes that is a metaphor. (At least, "in a curtain" is a metaphor. Usually phrases such as "like a curtain," "as a cat," etc. are considered metaphors.)

Answer 2

Etymology: Middle French or Latin; Middle French metaphore, from Latin metaphora, from Greek, from metapherein to transfer, from meta- + pherein to bear -- more at BEAR
1 : a figure of speech in which a word or phrase literally denoting one kind of object or idea is used in place of another to suggest a likeness or analogy between them (as in drowning in money) ; broadly : figurative language -- compare SIMILE
2 : an object, activity, or idea treated as a metaphor

The answer is YES.