Mort, what kind of facilities do you have access to, sprinting wise, during the winter? Do you have long hallways, an indoor soccer field, maybe an ice rink with a jogging track around the outside?
I ask because I live in Alaska and my situation is similar. My answer to the problem has been to use the jogging track around an ice rink for my sprints. I'm limited to 50M (with a hairy deceleration), but it's better than nothing. The trick is to only take your sweats off for 30 seconds at a time when its time to sprint.
Best I can do is a a 40m hallway (wall to wall) in our sports building which I use as best I can (20m runs). There is a 50-60m hallway (wall to wall) in one of our academic buildings but there are classes during the evening so I don't know if they'd appreciate sprint training outside the door 🙂