red alert

American

noun

(in military or civilian defense) the most urgent form of alert, signaling that an enemy attack is believed to be imminent.
the signal or alarm sounded for this alert.
a signal or warning that a critical situation is developing or has occurred.
the period during which a state of crisis or danger is declared to exist.

Etymology

Origin of red alert

First recorded in 1960–65

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

France's national weather service had issued a red alert for avalanche risk for the area on Thursday.

From BBC • Feb. 13, 2026

Mozambique has declared a red alert in the wake of the devastating floods while South Africa has announced a national disaster.

From BBC • Jan. 19, 2026

The grim toll, up from 2024, "is not just a statistic, it's a global red alert for our colleagues," IFJ general secretary Anthony Bellanger told AFP.

From Barron's • Dec. 31, 2025

Fresh floods struck Spain on Sunday as part of the northeastern Catalonia region faced a red alert for torrential rain, a day after downpours unleashed travel chaos on the Mediterranean island of Ibiza.

From Barron's • Oct. 12, 2025

Late Sunday night/early Monday morning Angela buzzed me with a red alert text, a link somebody had posted to the fan page set up by Nicole’s well-wishers.

From "Burning Blue" by Paul Griffin

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023