Weird Fantasy

From the introduction:

Supernatural storms are common in the Western Wastes, and most of them have dangerous, often deadly, side effects. One of the more unusual types brings an unexpected boon to such a dread place: spawning storms. At random intervals—typically no more than twice annually but often not recurring for several years—spawning storms brew in the Wastes, dangerous thunderstorms that unleash torrents of rain from clouds flickering with multi-colored lightning. Flash floods sweep through the barren hills and across the dust-laden plains, everything awash in uncontrolled magic and imbued with a wild fecundity. This is known as the mad spring.