I don’t know if Flow is supposed to be part of a longer story, but it reads like it. Rist comes from a short, Eskimo-like folk living in a frozen land with constant cloud cover. He jumps on a chance to accompany the party that rides chunks of iceberg down the river to warmer lands to sell. Most of the story is in the culture clash as Rist interacts with the strange (to him) warmlanders.
Rist’s people are short (and the women flat-chested). Their eyes are accustomed to the lack of sunlight, necessitating slitted goggles when he travels south, and farsighted, necessitating a braille-like written language carved into cylinders of wood. They ride giant land-bound birds and find the bones of real giants. Shepherding icebergs south is a lucrative trade. The southerners who buy the ice worship the sun and the moon, unknown to the northmen.
The fish-out-of-water story works ok, but isn’t exceptional. There are hints of an interesting larger world but not enough and too many of those too opaque. And it ends with only the barest climax, less suitable for a standalone story than for the end of a chapter.