Update note; never pull a sled with a rope. The sled has no braking and will crash into the snowmobile when stopping or slowing down. If you must, try sliding the rope into a length of plastic pipe with no slack on the ends. The pipe will keep the sled from sliding into the snowmobile. 

The recent snow storms reminds many of us that winter can be severe here is Pagosa Country and it is wise for those living far out country roads to be prepared. Here is a useful idea for a snowmobile pulled sled that could make a big difference when confronted with deep snow.