A backpack blower comprising: a frame operable to be supported by a user and including a back plate configured to be positioned proximate a back of the user； a housing supported by the frame and at least partially defining a chamber； a motor supported by the frame； and an impeller driven by the motor about a rotational axis to generate an air flow within the chamber. The chamber defines a channel region having a cross-sectional shape with an axial height and a transverse width, the axial height being greater than the transverse width, the axial height increasing from a first position proximate the back plate to a second position spaced from the back plate.
