I've just spent ~25 minutes coding this from existing knowledge, and using it alongside an answer I'd written to a question. During the time I'd spent putting my answer together, this question was deleted.
Was I warned when the question was deleted? No, I wasn't. My only warning came when I tried to post the answer (well, actually, undelete the answer as I'd accidentally posted it too soon previously):
alert() dialogue be put in place to immediately alert us when questions we're viewing are deleted?
This is similar to Display notification when the question you are answering is voted as dupe