Mazda 3 made awful noise yesterday, now it's gone?

Howdy, new poster here. Yesterday, I was dropping off a friend, and after a minute or so of being parked, when I started rolling forward again, this very loud, metal on metal screeching sound started coming from under my car, seemingly on the driver’s side. I thought there was maybe something under the car, but I looked, and found nothing. When I tried to leave her street the noise got so loud I was scared and stopped again, and her neighbors came out because they heard it. Again, examination of the wheels, undercarriage, under the hood, it all looked normal. Turning the steering wheel didn’t make the noise, but bouncing the hood made a slight squeak in the same area. So I parked it, and this morning had it towed to my mechanics. Of course, once it got there, they said it drove fine, they hear no noise, and saw nothing wrong with the brakes, tires, or axles. Basically, they think I’m crazy.
It was lightly misting when this happened but not real rain or anything. The mechanic said they don’t see any evidence that anything was stuck in there that might’ve gotten dislodged by the tow. I’m going to pick it up tomorrow, but is there anything I should have them check before that?

I once got a piece of gravel stuck in the brake dust plate that screeched like a banshee.
In this case I knew what it was…placed it in reverse extricating the rock…and drove off quietly.

Maybe ?

I did notice in the short time I was driving it that it seemed there was a point in the tire rotation where the noise stopped briefly - could it have just been a rock in the tread or something?

Oh yeah in case it’s relevant, it’s a 2007, about 60k miles on it.

I like the rock stuck in the brake rotor theory. Nothing else comes to mind.

Same thing happened with my 2000 Blazer, it made a god-awful screeching. A piece of gravel was stuck between the dust shield and the rotor. I was able to knock it loose with a thin screwdriver.

Ed B.

I had a 2008 F250 and it was a rock magnet. I have a long gravel driveway and sometimes it’s get a rock in the rotor several days on a row. Was you driving on a rock area?