A lot of people go overboard with animation, to the point where it's distracting. But these rain effects are pertinent to the entire strip even if the motion DOES cause a reader to sight it first. Very smart and tasteful.
This is going in my notebook titled "Things I Didn't Know about Surface Dwellers."
Wow, that was a fast response! Thank you both. I agree that having the animation take over would be a bad idea. As I get more comfortable with the technique, I can see how I would have to reign myself in from overdoing it.