Question

Why doesn't the smoke move along the ground?

Answer 1

Thanks for asking the question.
Doesn't always. Sometimes the smoke plummets towards the ground. This happens wen there is temperature inversion in the atmosphere. However, smoke rises upward because it is formed by ashes which are hot.  As hot air is denser then cold air so the smoke moves away from the ground or in the upward direction.
Hope I helped.