If you put your hand over the mountains, then the blue near the cabin looks like it's a lake, though it's not clear whether the lake is far below and the cabin is on a cliff or if the lake comes right up to the cabin. Of course, it's not a lake at all (unless you're going for surrealism in making a lake blend with the mountains), so perhaps either making the mountains a different color, or adding texture to the big empty blue area would have set it off better. Either that, or the mountains are really the tops of waves, and the cabin is about to go under o_O
Initially it was clouds on the bottom left, and a gradual fade from the darker blue to a lighter one, but my lack of experience ruined that plan and it became solid blue. You're not the first person to point it out it looks like a wave about to crash :) I think I painted the mountains a touch too high, closer to the middle of the canvas might have helped with the perspective.