The phrase "a major alert in" is correct and usable in written English.
It can be used when discussing significant notifications or warnings related to a specific context or situation.
Example: "The government issued a major alert in response to the impending storm, advising residents to prepare for possible evacuations."
Alternatives: "a significant warning in" or "a critical notification in".
It then crashed to the ground, sparking a major alert in the prison in the western suburbs of Dublin.
Last year, there was a major alert in Europe because of reports that Muslims holding European passports had received training in Qaeda camps and had returned to Europe with the intention of carrying out "Mumbai-style" attacks on civilians.
Last year, two bomb hoaxes in the centre of Canterbury caused a major alert in the city.
Given the current state of international relations, particularly with North Korea, it's hard to imagine how a simple human error could have resulted in such a major alert.
The NHS experienced the busiest week in its history last week, with record numbers of hospitals having to send patients elsewhere or declare a major alert.
The apparent, rapid disintegration of north-south relations comes against the backdrop of a major famine alert in South Kordofan and Blue Nile, where half a million people are reportedly in need of food aid.
Earlier this month, intelligence from a former member of Kashmiri's group led to a major terrorist alert in Europe.
At that time, his ability to temporarily evade British surveillance set off a major terrorism alert in the United States.
Colombian police are investigating the discovery of a box containing radioactive material, including uranium and plutonium, which has prompted a major security alert in the city of Cali.
"Spy Radiation: Major Alert," said a banner headline in The Evening Standard.
Last summer, the then future head of MI6, Sir John Sawers, was involved in a major security alert when his wife posted their holiday photographs on Facebook.
