You know... I have almost answered this maybe a dozen times. Both in the first incarnation, and the second. It's a question I struggle with.
I know a crisis after the fact. Rarely in one. Mostly, I think, because I'm busy. It's only afterwards, once things have calmed down, that I'm able to look back and go "Oh. Well, that was bad, wasn't it?"
Thing is... Once I'm actually able to see that XYZ is seriously in the Realm of Very Bad Things? I'm okay. Shrug. Crisis has passed. So it's time to sort out what's wreckage & what's salvageable. Sort of like depression. I almost never know when I'm depressed, either. It's only afterward when I'm like... Oh. Sleeping for 6 months? Absolutely zero interest in anything? That's probably depression, huh? Oops. Well, I'm better now!
When I'm edgy? I'm getting close to crisis, & need to rein myself in big time, while I've still got a shot at it. Because once I'm there? f*ck. I'm lost till I come out of it. If I come out of it. But I'm edgy all the damn time (exaggeration), while crisis is pretty rare.
I'm still not super-clear on what other people consider crisis. I know I've worried people / they've thought I was in crisis when I'm fine, & am just having a hard time. 2 weeks puking my guts out due to anxiety, and locked in flashbacks 10 hours a day, and nightmares whenever I do sleep? Shrug. Not that bad. It sucks, and I hate it, but it happens. I just need to not be around people so no one else freaks out and makes it worse. Or, even better, do be around people who breathe a little clarity & light into my life. Dark weighs less, then. <grin> Or a quick smack upside the head. Even better, that! ((Now if we could only somehow combine the two... ;) ))That was last month. Lost 2 & 3 weeks in Feb/March for similar if different. I'm used to it, and things can get much, much worse. That's not crisis. That's just things sucking.
For me, in crisis, I am out of my damn mind. I don't break very often, but when I do it tends to be hard and fast. I haven't done that lately, although I've been further off the Rez than I've thought I was. Vexing, that.
But once I've reached crisis? It's too late.