SO glad that it was not worse....what an awful flashback for you !!!!
Had the same thing happen to me last year with a Black&Decker iron...i have no idea how hot it got - but it burned/scorched the shirt i was ironing and the silver board cover underneath. I have a "thing" about anything electrical that gets "hot"...and never leave them plugged in....not toaster, coffee maker etc....reinforced by the time i plugged in my blow dryer and even tho i had not turned it on it went "POP" and caught fire.