Witnessed X5 on fire.

[JonK]

I was on my way from Mammoth Lake ski trip. It was 5 mile south of Bishop, CA around 7pm, 3/29/2012.

As I drop by I saw the nice clean silver post-face lift E53 on the other side of the freeway. Older gentleman had the hood open while inspecting the white smoke coming out of the engine. As I drove further I could see the white smoke instantly growing into more darker smoke from my rear view mirror, I had to assume it has to be more than steam coming from blown head gasket considering the color. It kept on growing higher and higher had to be at least over 80 feet in the air.

I was concerned about the gentleman's safety. However, neither did I had a chance to take a picture under the circumstances, nor went back to assist him.

Very somber experience, I must say. I was in a literally a same car.
Engine caught on fire? Why could that be?