[Brucelee]

Generally speaking, the tires fitted on the Box are pretty bad in the rain. They are normally summer performance tires and handling in the wet car borders on dangerous.
Given where you live, this is normally not an issue but a reason to slow down when it is raining. I may also signal a need to look for a better rain tire when you replace your current tires, which I would hope would be real soon!

Now when the water builds up, the danger is double for hydroplannng. Other then the low ground clearance, the Box is superbly set up for handling in the wet. I chalk it up to the tires (20K is a lot of miles on any set of Box tires) road conditions and perhaps your speed at the time.

Just my two cents. Drive safely.