It does depend on the snow. I skipped my weekend runs as the snow had frozen overnight on Friday leaving a thin crusty layer of snow on top of ice. This was impossible to run on.
Woke up this morning to a powdery white covering of new snow (weekend stuff having melted away yesterday) that was great to run through.
You won't lose that much fitness over the wekk of disruption, and its due to disappear by this weekend. So I wouldn't worry too much.