yellow alert

American

noun

(in military or civilian defense) the first alert given when enemy aircraft are discovered approaching a military installation, city, coastline, etc.
the signal or alarm sounded for this alert.
any primary stage of alert, as when toxic chemicals have escaped in a particular area and a potential hazard exists.

Etymology

Origin of yellow alert

First recorded in 1965–70

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.

Parts of the west Highlands, Argyll and the Western Isles saw heavy snow after the forecaster issued a yellow alert.

From BBC • Apr. 5, 2026

A yellow alert for snow and ice is in place for Counties Donegal, Cavan, Monaghan, Louth and Connacht.

From BBC • Jan. 5, 2026

The Spanish island also issued a yellow alert for thunderstorms, from 08:00 until 18:00 on Tuesday.

From BBC • Sep. 30, 2025

North East England, North West England, Yorkshire and Humber and south-west England have a yellow alert for the same period.

From BBC • Aug. 11, 2025

Until further notice, we must proceed under a yellow alert during daylight hours and a red alert at night.

From The Test Colony by Marks, Winston K.

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