Remember, ice will expand to the least restrictive space. If it was open, it probably would expand to the air. Chances are the sliding track is iced but may be ok if it expanded into the air. I'm under shed and with the winds, I had about 2' of snow on our deck. Cleaned it off yesterday to minimize the potential damage during the thaw and re-freeze. So far we've been ok during this type of stuff, but I do lay awake at night thinking...... Do you have a back drop you can put over it? I've always shrinkwrapped on land (except for one year I used the blue tarp but I won't go into that right now-cluster f***) due to the potential issues. You very well may be ok dependent on factors...... Regardless, it is what is done. If you posted pics, you may get more responses. I wish you luck! I'll be going back to the boat tomorrow before the 'big' freeze for a couple days. I have some anti freeze I'll pour into the tracks if I see any potential problems. Oh the joy!!