Does snow dull a saw?

[Trilliumrock]

I do most of my crosscut sawing during the winter so this question keeps coming up. Is it a big deal to saw through snow caked onto tree bark OR have the saw end graze snow (see pics). Obviously, it is preferable to have the saw only contact the wood intended to be cut. However, removing the snow or moving the log away from the snow takes energy (sometimes in limited supply!). Does sawing through snow or ice significantly dull a saw?

[Trailsawyer]

I wouldn't worry about a little snow dulling the saw, however what is hiding under the snow could!
We have a lot of "dirty" bark in our area... so I normally remove the bark before cutting, especially if a tree has been down very long.
One nail can ruin your day, so extra caution is needed around fence lines or campgrounds!

[PATCsawyer]

Doubtful. I've done a lot of winter sawing and never had a problem with snow, though I usually debark the trees I cut and that removes most snow in the process. Winter sawing can mean frozen wood. I've sawn through frozen hemlock knots without incident that I wouldn't think of chopping. The normally singing saw changed its tune to the sound of sawing through glass -- a real screech. Though unnerving, I found no damage to the saw's teeth. Those same knots would've been an axe destroyer.