Ok, this is me rambling again, considering the map. The Big Map, because this only really works if you include the Crimson Savanna, and it helps to have the Curse of Rajaat.
So, if you look at the Tyr Region as it is today, it really sucks as a place to settle; you’ve got a few places with water, and those have big populations, but most of it is a flavor of dry wasteland. If you go a bit north or a bit south of the Tyr Region (really, the Ringing Mountains), you get scrub plains which, while not the best thing ever, are at least better watered than the Tyr Region.
And we know why it’s better watered; the Crimson Savanna has a better water cycle. Rivers flow down to the base of the cliffs, water evaporates, condenses, and comes down as rain. Some of that pushes west, watering the Hinterlands and the Forest Ridge, but the Ringing Mountains prevent it from reaching the Tyr Region.
So why settle the Tyr region like that? Because it used to have water, and it used to have a water cycle tied to the sea. Rivers and lakes (the Dragon’s Bowl might well have been a decent-sized lake at one point) provided a decent hydrology, and the cities were no doubt on such water sources. When defiling dried up the land, so too was water destroyed. This is all basic stuff.
But we get back, as I usually do, to the Cerulean Storm. Because this puts water back into the cycle; if it doesn’t start reversing the further desertification of Athas, it at least significantly slows it, just because of the sheer volume of rain coming down. And while a gallon of water on silt turns into a tiny mud flat, gallon after gallon after gallon is going to, eventually, just make clouds. Natural clouds, made of evaporated water left behind by the Tyr Storms.
I used to live in Houston; I’ve seen my share of hurricanes. But I think this might be part of the future of Athas… while a Tyr Storm is destructive, it’s also localized… it’s Tithian’s breath weapon, a line of destruction hundreds of miles long. A hurricane, though might be hundreds of miles across… Hurricane Sandy, in 2012? It was more than a thousand miles wide. It could have its eye at the Silt Archipelago and still be hitting Tyr at the same time
And the idea of a hurricane hitting the Tyr Region? That’s amazing. Seers waking in a cold sweat for weeks, seeing a wall of water washing over the region, a sense of menace deep within the vision. A type of destruction they’re utterly unprepared for, that they can’t hunker down and get through. Sun-baked bricks melting before wind and rain that might last days. An entire harvest ruined across the Tablelands, not just the Tyr region.