A big river swamp, like the Savannah River here, very close to my farm, is about as grey and featureless a place as I can imagine when a fog or drizzly rain rolls in. Spanish moss, tree trunks, the ground and the sky are all the same color. A snowstorm in the mountains must be a lot the same. Been turned around in the swamp a few times following someone else, but always found my way in an hour or so. "All sloughs lead to the river", is a saying that was drilled into me from an early age.
In my older age I can appreciate the words of an old swamper who told me once, "You ain't lost if you don't care where you are". How true.