A system and method are provided for detecting an impending stall or surge in a radial compressor. The system and method may include a plurality of detection devices configured to detect a transition of a low momentum zone of a gas flow through the diffuser from a first position adjacent a shroud wall of the diffuser to a second position adjacent a hub wall of the diffuser. The system and method may also include a control system electrically coupled to the plurality of detection devices and configured to receive a plurality of information signals. Each information signal may be transmitted by a respective one of the plurality of detection devices and may correlate to a location of the low momentum zone. The control system may be configured to process the plurality of information signals and detect the impending stall or surge based on the location of the low momentum zone.