Don't be another victim of Leica's rip-off repair scheme!!
Over here in the UK (and probably the US, Europe etc too) this is quite a well known problem with the 77 Televids. I know of at least 3 people personally who have had the same problems, even in the much less harsh conditions here. It seems that with some samples of this scope the coatings just don't take well to the objective, and literally dust off with very minor rubbing (actually just the kind of rubbing you'd do when carefully cleaning any other make of scope). The scopes have been back for repair under warranty 2-3 times, and each time the same repeated problem! Attaching a filter seems to be the only long term solution after repair.
To add insult to injury Leica then accuse their precious customers of mistreating their optics, exposing them to salt (birding at the coast!) etc, etc.
To be fair to you, all you did was take a (supposed) top make of scope into a difficult environment and use it for what it was designed for, just as the likes of Swaro, Zeiss, Nikon etc recommend users of their scopes to do. After all, does it say anything in the literature of your scope about not taking it to the arctic? cleaning the lens etc?
I'm not sure what can be done, but I'm sure there's an old thread somewhere on BF about this exact problem. Worth doing a search for it. It's got to be worth kicking up a fuss and throwing the problem back at them, in light of the fact that you now know that you are not alone with this problem. Leica also know this, but will assume you are ignorant of the issue! Failing this, would your insurance company cover the damage? Don't accept any responsibility for the fault, and remove any evidence of this from your thread before you cite BF as further proof in support of your cause.
Good luck with it, Steve