So... the quick answer? Its an impossible geographic situation. Ok. Gary Gygax was not a geologist or geographer, and I'm not going to hold it against him. Can we try to explain it? You betcha!! Its magic! Ok. I'm not being fair, especially after the post I just made over in the "
Poll: Fantasy world maps and real world geology" thread! But the two outflows of the Nyr Dyv certainly
is an example of a situation that merits this kind of attention, so I actually did come up with an explanation using the dimensional distortions that sank the Isles of Woe. Check out the "Addendum: The Geography of a Cataclysm" section at the bottom of my
The Isles of Woe webpage for a more detailed explanation that you may or may not find believable.