Horrendous Squealing Scraping Noise, Front Wheel

Our Prius is only a year old with less than 9,000 miles. Everything has been fine with it and then yesterday I took it out of the garage and started to drive and there was the most horrendous grinding/squealing/scraping noise as I started moving from the front passenger side (UK passenger, so left looking out).

I stopped the car and had a look, as at first I thought I was dragging something, but nothing to be seen. Checked the parking brake was definitely not engaged. I then thought perhaps something is caught in the brake pads and it will go in a bit, however even hard braking didn't seem to change the noise at all.

Carried on (I was going about 7 miles), and as I drove it would gradually get quieter, and then get louder again, with the occasional "clang" sound almost like a spring under tension suddenly moving.

Towards the end of the journey it had started to go quieter again, but with the window down you could still hear constant squeal/grind.

Parked the car, was away for an hour, came back and set off home and the noise was totally gone. Entirely silent all the way back home! Now I don't know what to do - whether it will come back, or whether I should take it in to garage for them to look (even though it's now not making any noise).

Any ideas what it could have been?

 

It would have to be weekend if I did as it's dark when I leave home and when I get back from work just now (I cycle). But yeah it's still under warranty. My other half is bringing it in tonight to pick me up so I'll see what it's like on the way home.

 

Yeah - I'll see if I can have a look this weekend (when I have some light!). It hasn't made the noise since. Actually at the end of the journey where it was making the noise, I reversed into the car park space, and I wonder if the action of reversing allowed whatever it was to come out, which is why it had magically stopped when I returned to the car an hour later.