How did the car stop, abruptly, or did it just lose forward power and the engine freewheel with a kind of high frequency (not crunching) grinding like noise from the rear of the car? The CV axle may have just snapped out of its seat in the differential as one member here experienced a short while ago after spinning his wheels on a slippery road, affecting the same side. Sounds like the Tow man looked under the car and listened.
Don't guess at this one, have someone get under the car and look, it may be an easy fix. You can probably see both axles at their insertion point into the differential from the rear of the car if you kneel down low enough, if you can, look for excessive space on one side between the joint and the differential by comparing both sides.
More detail about the car would be helpful also, particularly drivetrain specifics, awd, manual/auto.