Yellow Alert is an alert signal used on Starfleet starships and facilities.

In 2254, Captain Christopher Pike ordered the USS Enterprise to yellow alert anticipating attacks from rogue elements in the Marrat Nebula. (EV comic: "The Fires of Pharos") Generally, in the 23rd Century, this precaution is unusual at a spacedock, when starships are on the ready inside. A flaw of yellow alert status in this time was that minor warnings in the ship data banks didn't process a likely red alert event. Such as a faulty module lives depend on for safe beaming. (TOS movie: Star Trek: The Motion Picture) Also, starships were prone to overloads when key crewmembers were unavailable to man posts. (TOS movie: Star Trek III: The Search for Spock) In the 24th, sensors automatically raise shields and prepare computers for whatever outside stimuli dictate. One design flaw also corrected was the minimization of shipboard communications and readings that warrant unwanted scanning. (TOS episode: "Balance of Terror") Warp engines and impulse thrusters also have their power signatures masked by background subspace static or natural space phenom. Certain actions cannot bypass yellow alert. Such as using a tractor beam, de-pressurizing a deck, or within the gravity field of another planet. Performing or receiving sensor sweeps usually illicit this as well. (TNG episode: "When the Bough Breaks" , Star Trek: Starfleet Academy (game) (SNES))

Aboard the USS Enterprise-D the yellow alert led to all bridge stations becoming fully active and enabled, with diagnostics of the tactical and primary systems. Also, the operations manager would also limit activities that could be a "hinderance" to emergency preparedness. (TNG video game: Echoes From the Past)


Wesley Crusher once (correctly) monitored, but (without authorization) responded to such a trigger, while seated on the Enterprise-D bridge/conn. (TNG episode: "Encounter at Farpoint")

Yellow alert is more often done "manually", by vocal command; from a foreseeable dilemma. "Automatic" comes into play when a physical disturbance occurs near/to the ship's hull.


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