A plow apparatus (110, 210, 310, 410, 510) for use with a vehicle, said plow apparatus comprising: a support frame (114, 212, 312, 514) configured to couple to the vehicle having a forward travel direction and vertical and lateral axes perpendicular to the forward travel direction; a debris-pushing plate assembly (116, 316, 416, 516) coupled to said support frame and comprising: a center plate (118, 318, 418, 518) having a center portion coupled to said support frame; an extendable plate (120, 320, 420, 520) having a first end pivotably coupled to an outboard end of said center plate and pivotable about a sweep axis (128, 528) that is parallel to the vertical axis of the vehicle, characterised in that a second end of said extendable plate is pivotable more than one-hundred eighty degrees about the sweep axis and said extendable plate is pivotable between a stowed configuration in which said extendable plate extends laterally inboard alongside and parallel to said center plate, and a plurality of extended debris-clearing positions in which said extendable plate is laterally outboard of said center plate; and a sweep actuation mechanism comprising a sweep actuator (144, 324, 424, 544) coupled between said extendable plate (120, 320, 420, 520) and said center plate (118, 318, 418, 518) and operable to pivot said extendable plate about the sweep axis (128,528); wherein said apparatus is operable to clear snow or debris from a ground surface adjacent the vehicle with said center plate (118, 318, 418, 518) and said extendable plate (120, 320, 420, 520) in both the stowed and extended configurations. a support frame (114, 212, 312, 514) configured to couple to the vehicle having a forward travel direction and vertical and lateral axes perpendicular to the forward travel direction; a debris-pushing plate assembly (116, 316, 416, 516) coupled to said support frame and comprising: a center plate (118, 318, 418, 518) having a center portion coupled to said support frame; an extendable plate (120, 320, 420, 520) having a first end pivotably coupled to an outboard end of said center plate and pivotable about a sweep axis (128, 528) that is parallel to the vertical axis of the vehicle, characterised in that a second end of said extendable plate is pivotable more than one-hundred eighty degrees about the sweep axis and said extendable plate is pivotable between a stowed configuration in which said extendable plate extends laterally inboard alongside and parallel to said center plate, and a plurality of extended debris-clearing positions in which said extendable plate is laterally outboard of said center plate; and a sweep actuation mechanism comprising a sweep actuator (144, 324, 424, 544) coupled between said extendable plate (120, 320, 420, 520) and said center plate (118, 318, 418, 518) and operable to pivot said extendable plate about the sweep axis (128,528); wherein said apparatus is operable to clear snow or debris from a ground surface adjacent the vehicle with said center plate (118, 318, 418, 518) and said extendable plate (120, 320, 420, 520) in both the stowed and extended configurations. a center plate (118, 318, 418, 518) having a center portion coupled to said support frame; an extendable plate (120, 320, 420, 520) having a first end pivotably coupled to an outboard end of said center plate and pivotable about a sweep axis (128, 528) that is parallel to the vertical axis of the vehicle, characterised in that a second end of said extendable plate is pivotable more than one-hundred eighty degrees about the sweep axis and said extendable plate is pivotable between a stowed configuration in which said extendable plate extends laterally inboard alongside and parallel to said center plate, and a plurality of extended debris-clearing positions in which said extendable plate is laterally outboard of said center plate; and a sweep actuation mechanism comprising a sweep actuator (144, 324, 424, 544) coupled between said extendable plate (120, 320, 420, 520) and said center plate (118, 318, 418, 518) and operable to pivot said extendable plate about the sweep axis (128,528); wherein said apparatus is operable to clear snow or debris from a ground surface adjacent the vehicle with said center plate (118, 318, 418, 518) and said extendable plate (120, 320, 420, 520) in both the stowed and extended configurations.