The phrase "alert stage" is correct and usable in written English.
It can be used to describe a condition or phase where someone is attentive or aware, often in contexts related to safety, health, or readiness.
Example: "During the emergency drill, all personnel were required to be in an alert stage to respond quickly to any situation."
Alternatives: "vigilant state" or "ready condition".
Greg Warren, a spokesman for the Transportation Security Administration, said there was no heightened alert at the nation's airports after the incident, because they were already at the highest alert stage.
In May 2009 the Butte County Department of Water and Resource Conservation reported that due to lack of rain and groundwater withdrawals, 37 of the 81 wells monitored were at an "alert stage" requiring irrigation coordination in the county.
The WHO declared a pandemic alert stage 6 due to an outbreak of an influenza A virus (A/H1N1) on 11 June 2009.
Dreams that occur during alert stages.
Mexican officials raised the alert level to stage three due to the threat of Barry.
On June 22, the Sistema Nacional de Protección Civil (National System of Civil Protection) in the Mexican state of Jalisco raised the alert level to stage two for coastal areas.
However, the five-stage combat alert level remained at DEFCON 4, the second-lowest level.
In El Salvador, officials raised the disaster alert level to green, the lowest stage of alert, on November 5.
The most severe alert -- a Stage 2 -- was in the east San Fernando Valley, The Times reported the next day, and the other 15 alerts affected wide swaths of the Los Angeles area and Inland Empire.
On top of these alarms, a further 104 lower-grade, but still serious, flood warnings were issued across western England, as well as another 206 flood "alerts" – early-stage indicators for households and the emergency services to be prepared for possible flooding, The wet weather is set to continue, with much of the country facing downpours into next week.
The National Disaster Prevention Centre (Cenapred) raised the alert to "yellow stage three" - the third-highest level.
