If a steel cable snaps the weight or 'mass' of the cable will keep it moving, and it can cut you in half.
Hey! Didn't mythbusters bust that myth!
(cutting a person in 1/2, but doesn't mean I want to get hit with one anyways.)
Recommended is 1.5 the vehicle weight. If you buy an inexpensive winch, get the biggest you can afford.
A snatch block is worth its weight in gold.
