[TOMT] [MUSIC] Remember the YouTube video, don't remember the name!

I'll do my best to describe:

• Atmospheric music, orchestral?
• Name was some sort of klyataclysma-sounding word, that was misspelt (like that) I think?
• I am remembering this from 7+ years ago when I listened to over 30mins of this groups' songs, each was 30mins to an hour long.
• The video I remember had clouds of some sort.
• I think it involved string instruments, at times with "epic" sounding chords, always lyric less

Anyone have a clue on what it might be that I remember listening to? It's so long ago and I can't spell it (I don't think it was a real word) so it's been fruitless googling for the past 20 mins.

Thanks Reddit!