A Three-Stage snowblower uses one set of lower speed augers to draw in snow and ice then a second to break it up even more and finally a third higher speed impeller to propel the snow out of the discharge chute.
A Dual or Two-Stage snowblower uses one set of lower speed augers to break up snow and ice and then a second higher speed impeller to propel the snow out of the discharge chute.
A Single-Stage snowblower uses one impeller to break up snow and ice and then propel it out of the discharge chute.