Question: what is the difference between a single and double stage snow blower?
Answer: In single-stage models, the auger performs double-duty: it both sucks up and discharges the snow. Whereas in two-stage models, the auger is devoted exclusively to the task of sucking up the snow off the driveway while a separate gizmo, called the "impeller", is responsible for discharging the snow out of the chute.