Is it possible for "it is snowing" to be acceptable"? I was told that "tha an t-uisge ann" can render "it's raining", so can "tha sneachd ann" really only express that there is snow = snow is lying, rather than that's it's actually falling?
"Oh, dear" is what Duolingo wants. I think "Òbh, Òbh" is simply an exclamatory phrase. I believe you are correct that "dear, dear" would be an equivalent exclamation, though it isn't exactly the answer for this exercise.