Keep them crossed Alan it'll be OK. It's just one of the risks that you take when you go skiing early / late season. We know what the risks are and have to be prepared to have some bad luck. You can't let it spoil your holiday if it doesn't snow you just have to make the most of it.
I don't think you are going to find many insurance policies now that will insure you for a lack of snow. Surely no insurer will accept a new policy at this stage bearing in mind the chance of no snow is quite large.
It is for this exact reason why I always renew my multi trip annual travel insurance policy that covers winter sports (including off piste skiing). I also found that by doing it this way it works out cheaper.
I have just booked my insurance with Columbus Direct. If you go for their "Super" Insurance it will pay £40 per day each for piste closure. For a family of four for one week it cost me £46.00. Not bad, and worth the risk.
you will not find a company that will cover total holiday cost, reason they will argue that you have benifitted and enjoyed your hotel accommodation and if half board eaten the food, which is the bulk of your holiday the no snow cover is for the lift passes so £20 to £40 a day would cover that. you will have to make the most of it if no snow but you should get some by new year,