Thoughts ?

I don't see anything wrong with it. Lots of authors use the device.

I would think that would be fine as well as long as everything flows appropriately after that first line.

A nuke was dropped on New York City and flattened the place. Yeah, you know how it goes, one thing led to another and that was the way it had to go down. Oh! I see you're confused, well, let me catch you up to speed.

Like that? Sure, why not?

I like indianroads example. It's really a bombshell, the voice is interesting, etc.

But - the 'catch you up' better be short and fast: no going back to the building of New York, no spending the whole book moseying along to the big explosion.

I just finished reading The Tie that Binds by Kent Haruf and it begins with the 80-year-old woman chained to a hospital bed and charged with murdering her brother. Then Haruf spends the next 350+ pages going back a century and giving all of the story that led to that point.

I'm a novice so take my opinions with a healthy dose of salt.

I see en media res as a good suggestion, but prefer to start off just before the poop hits the air conditioning. As in, you have a big event in mind, but rewind your mental image of it a little bit, and start from there. That gives me from a half to a full page to lightly sketch the world, and vaguely introduce the characters. I go back after the event to fill in the details.

From my recent novels and WIP for example.
Departure begins with soldiers chatting at the top of a city wall. Scene character sees something suspicious - a dog - dog turns out to be a robot bomb, which blows up.

Desperation begins with MC standing on an elevator platform. People are coming after them (brief explanation of why). Then the shooting begins.

Damnation (WIP) begins with MC waking up in the early morning. He's in an underground shelter, and feels an earthquake. Things escalate quickly and (as my partner likes to say) a zany adventure ensues.

Starting just before the event gives you time to let the reader understand at least the who, what, and maybe where of the 5 basic questions.

Again though, I don't know what I'm talking about most of the time, so YMMV.

Something mysterious helps as well. Octavia Butler's Kindred begins with her arm missing and she can't explain it to the police and hospital staff who want to blame her husband. The actual cause was even more mysterious. The story starts and ends up back with the hospital scene.

Great book!