Explaining the Plowing Cycle

What happens here

Returning to the car, the man explains that during snowfall rates of half an inch to an inch per hour, it's impossible for snowplows to keep roads perfectly clear. He states that plow trucks operate constantly on main roads and highways, but by the time a driver encounters a freshly plowed section, new snow will have likely fallen in the interim.

Goal: Clarify the continuous nature of plowing versus continuous snowfall