What's this noise?

My wife and I just completed our first relatively long trip in our new Prius. We traveled about 250 miles each way to visit my folks. We now have around 1200 miles on the car.

On our way home yesterday, on the highway, doing about 70 mph, we heard a loud metalic noise. Hard to describe, the sound was a high frequency metalic sound, almost like a metal crease had popped. The sound was definitely some sort of metalic expansion-like sound. The sound might have been from the right rear area but hard to say exactly. It didn't sound like I hit something in the road.

I read in the manual about "pinging" from the hybrid system. I suppose this could be a "ping" but just one loud one.

So the question is: Ignore this and figure it was just one of those new car sounds as things settle in? Or rush to the dealer to report an anomaly? Everything seems to be working just fine.

Any thoughts?

 

The sound seemed like too high a pitch to be road debris. But it was over in an instant and the car seems fine. No more sounds and no problems. I'm still wondering it something, like the battery, went through some sort of expansion.