Highstorms are a pretty important feature of Roshar.

• Frequency is defined by math formula
• Frequency varies, rather than being a static every x days
• Localised to a specific range of x coordinates (instead of full dimension raining)
• Crem to fall as part of the storm
• Crem that reaches a full block turns into hardened crem stone
• Gemstones should charge when in a highstorm (and should be instantly full)
• A highstorm might launch entities

References:

This mod has sandstorms, which has a build up of sand piles while active.
https://legacy.curseforge.com/minecraft/mc-mods/weather-storms-tornadoes