Yellow alert

A yellow alert (also condition yellow or code yellow) is the second highest alert signal status on Starfleet vessels, one stage below red alert. It designates a ship-wide state of increased preparedness for possible crisis situations. In this status, shields and deflectors are brought to full power, however the weapons systems remain off line.

A yellow alert may either be activated manually by the commanding officer in preparation for a tactical or environmentally hazardous situation, or automatically upon detection of unknown or hostile spacecraft, or upon detection of certain system malfunctions. If the situation escalates, the commanding officer or the main computer will order a red alert.