Without water to hold the ocean bed together, the deepest valleys and trenches have filled with The Silt. This is a heavy, fine, fluid-like volcanic ash and dust. From a distance, it looks like a calm, gray sea, but it behaves exactly like water. It forms slow-moving gray currents that can drown an armored traveler who steps off the path. Standard wheeled carts sink instantly; survival requires specialized sleds, stilt-shoes, or multi-legged beasts.