I have a nice big purple Phormium that got a bit squashed in teh snow. Quite a few leaves have died off too. So, the other day I just pulled off (not cut) the dead leaves - you have to pull quite hard, but they should come off if they're properly dead. If they don't pull off, leave them for another time. Personally, I wonldn't remove the living leaves, but I doubt they lift back up in this case. If they're really bothering you, cut them off close to the ground. You could just wait and see for now tho!

I'd be inclined to leave them till mid March/April and then remove any dead ones, plus cut off any laying too close to the soil.

i do mine when frost has gone, then pull off dead leaves, soon grows again, ive had mine quite a few years and still with me,