I feel for you, while my slides weren't out I was concerned with the snow build up on mine, here in SE PA. There was actually 2 layers of ice due to the 2 sleet storms we had between the last 3 snow falls, so it totaled almost 9" of very firm snow and ice.
My son and I threw a length of nylon rope over the roof and used it to saw through the top and middle layers and then pulled it towards the ends in 3 sections. Then were able to get up and break it loose in a few large chunks.
There was still another intact 4" layer of ice, but I figured I got at least half the weight off. I have a whole new respect for how much weight the roof of mine can hold as the pile of what we got off the roof was a chore in itself to clean up.
Ont thing I would do is lift the front higher so when the melt down comes, it'll be able to run off quickly.