While the damage sandstorms cause is pretty evident the moment it hits, it'd be nice if around the edges of the storm the wind picked up and there was the sound of sand blowing against the hull, until you were right in the middle and the wind was really howling (maybe even the noise of the engines spluttering as they become clogged up with sand - although I'm not suggesting change the mechanics of the clouds themselves to cause an effect like that).
Other than looking slightly different from other clouds, I don't know if there's any way of determining if a cloud is a sandstorm or not without flying into it. Certainly I've had my fair share of encounters with clouds that looked dangerous only for them to have no effect, and likewise have been seriously damaged by clouds that looked no different from their surroundings.. so visually assessing them is a bit hit and miss.
While making them visually more distinctive would make it easier to avoid them, it might make it too easy.. with a sound effect it would be more subtle, and would only really make navigating them easier when out of battle, when it is easier to listen for.
On top of being more atmospheric (literally!) it would give experienced & cautious crews a slight edge over the more gung-ho crews that charge through clouds blindly, since it would leave their ships in slightly better condition when entering fights.
