I left the windows rolled down and it poured hard here. After a few minutes of pouring the alarm went off. It was pretty loud and seemed to come from the engine. I popped the keys in and started the engine and switched it off. After doing this a couple times, the alarm went off. Is this a cause of concern?

 

It's very possible the rain set of the motion sensor in the car, I wouldn't be too alarmed (pun intended.)