Cooling apparatuses and methods are provided for facilitating cooling of an electronic device utilizing a cooling subassembly, a pump and a controller. The cooling subassembly includes a jet impingement structure, and a thermosyphon. The jet impingement structure directs coolant into a chamber of the subassembly onto a surface to be cooled when in a jet impingement mode, and the thermosyphon, which is associated with the chamber, facilitates convective cooling of the surface to be cooled via boiling of coolant within the chamber when in a thermosyphon mode. The controller, which is coupled to the pump to control activation and deactivation of the pump, also controls transitioning between the jet impingement mode and the thermosyphon mode based on a sensed temperature of the electronic device.