Is it ironic to write on a dry-erase board with a permanent marker?
From dictionary.com
" Ironic literature exploits, in addition to the rhetorical figure, such devices as character development, situation, and plot to stress the paradoxical nature of reality or the contrast between an ideal and actual condition, set of circumstances, etc., frequently in such a way as to stress the absurdity present in the contradiction between substance and form"
Since the event contrasts ideal and actual, I would say it is ironic.