A portable floor surface and method of use thereof facilitates unloading side-by-side cargo carts disposed in laterally spaced relation with an aisle defined between them. The floor surface has a body with opposite front and rear ends and lower and upper surfaces extending between the front and rear ends. The upper surface is brought into a generally flush relation with the floor of the cargo cart when the lower surface is resting on a common floor surface with the cargo cart. A ramp surface extends at an upward inclination from the front end toward the rear end and a latch member operably associated with the body is adapted for operable engagement with a first cargo cart to releasably lock the portable floor surface to the first cargo cart.