With the fuel filler neck on that side, I'm guessing it caught fire and the gas inside the tank provided an extended source of energy for the fire to burn.
Of course, I have a degree in business so I may not have fucking idea what I'm talking about.
or judging by the design of the car and rims, the car might have been doing a burnout that caught on fire, with the gas tank so close to a fire, the car just started burning and the gas provided the fire with an extended source of energy thus melting the alloy wheel.
I too have a degree in business and have little to no idea what I am talking about.
EDIT: TO YOU evilbob below...YEA IT DOES CAUSE A FIRE... !!!
aluminium melts at 660 °C (933 K) that's pretty normal for a bigger fire (aluminum and 1220 °F for our non SI units friends)
Careful, the T-1000 can reform after being melted.
But he can only reform into a wheel.
I'm a third-degree black belt in English
This looks like the remains of a vauxhall vectra which is front wheel drive so no burn out sorry
Or a little bit more, for most alloys.