Warning:this footage may be distressing to some viewers.
At 3.20pm on Wednesday, November 25, Peter Rosenfeld and Vera De Ruiter were heading south on the A82 between Tarlee and Gawler.
They saw a massive dark cloud and assumed it was a weather front.
What happened next was captured in this horrific film and should be a lesson to all.
Video via Peter Rosenfeld/YouTube.