The phrase "alarming hours" is correct and usable in written English.
It can be used to describe times that are concerning or troubling, often in relation to events or activities that occur late at night or very early in the morning.
Example: "The party went on until alarming hours, leaving the neighbors quite disturbed."
Alternatives: "worrying hours" or "disturbing hours".
The studio will host an alarming 20 hours of continuous live election news programming starting at 9.55pm tomorrow evening, and ending at 6pm on Friday.
"Massively multiplayer" online games such as "Legend of Mir 3" and "MapleStory" have legions of devoted fans who spend an alarming proportion of their waking hours sitting in front of their PCs, at home or in internet cafés, doing battle with elves, wizards and mythological beasts.
And it was rising at an alarming rate — about an inch an hour.
He was right, too: the most alarming thing about that last half-hour was that nothing in it really came as a surprise.
And the lab report with alarming blood results was time-stamped three hours after he was sent home.
Arriving catatonically knackered, barely able to utter a syllable, I was in terror at the sight of the programme: dawn runs, at least five hours' cardio a day, an alarming amount of "burpees" (squat thrusts).
It averaged a 1.9, a number made more alarming because its main competition in that hour, "Hawaii Five-0" on CBS, presented a repeat Monday night.
As with any media bubble, variations of the story surfaced within 24 hours, making it seem like another alarming American trend, the kind in which AM-radio hosts go headhunting for someone to blame.
Texts, if they ever make it through, take hours; calls are dropped at an alarming rate, even by AT&T standards; and Internet access is essentially impossible.
The act of watching becomes charged in an hour that is sometimes uncomfortable, often alarming and ultimately irresistibly joyous.
